United States Patent (19) 11 Patent Number: 4,734,514 Melas Et Al

United States Patent (19) 11 Patent Number: 4,734,514 Melas et al. 45 Date of Patent: Mar. 29, 1988

54 HYDROCARBON-SUBSTITUTED ANALOGS Organometallic Compounds of Arsenic, Antimony, and OF PHOSPHINE AND ARSINE, Bismuth, pp. 120-127. PARTICULARLY FOR METAL, ORGANIC Hagihara, et al., Handbook of Organometallic Com CHEMICAL WAPOR DEPOSTION pounds (1968), pp. 560, 566, 571, 574, 579,581. 75 Inventors: Andreas A. Melas, Burlington; Hagihara, et al. Handbook of Organometallic Com Benjamin C. Hui, Peabody, both of pounds (1968), pp. 720-723, 725-726. Mass.; Jorg Lorberth, Kisolapoff, et al., Organic Phosphorus Compounds, Weimar-Niederweimar, Fed. Rep. of vol. 1, pp. 4-11, 16-27. Germany Kuech, et al. "Reduction of Background Doping in Metal-Organic Vapor Phase Epitaxy of GaAs using 73) Assignee: Morton Thiokol, Inc., Chicago, Ill. Triethyl Gallium at Low Reactor Pressures', Appl. 21 Appl. No.: 828,467 Phys. Lett., Oct. 15, 1985. TZSchach, et al., Zur Sythese Zeitschrift fur Anorganis 22 Filed: Feb. 10, 1986 che und Allgemeine Chemie, Band 326, pp. 280-287 (1964). Related U.S. Application Data Primary Examiner-Paul F. Shaver 63 Continuation-in-part of Ser. No. 664,645, Oct. 25, 1984. Attorney, Agent, or Firm--George Wheeler; Gerald K. 5ll Int. Cl* ...... CO7F 9/70 White 52 U.S.C...... 556/70; 568/8; 57 ABSTRACT 568/17 58 Field of Search ...... 556/70,568/8, 17 Organometallic compounds having the formulas: 56 References Cited U.S. PATENT DOCUMENTS x-y-y H 3,657,298 4/1972 King et al...... 556/7OX OTHER PUBLICATIONS wherein N is selected from phosphorus and arsenic, His Kosolapoffetal, Organic Phosphorus Compounds, vol. hydride, and X and Y are independently selected from 1, pp. 109, 110, 111, 114 to 119 (1972) Wiley-Inter hydride, lower alkyl cyclopentadienyl, and phenyl, science, N.Y. except that Y cannot be hydrogen; and Kosolopoff, Organophosphorus Compounds, John Wiley & Sons, Inc., N.Y., pp. 30, 31 (1950). MR Doak et al, Organometallic Compounds of Arsenic, Antimony and Bismuth, Wiley-Intersc., N.Y., pp. 126 (1970). wherein x is an integer from 2 to 4 inclusive, each said Chemical Abstracts 100 174916b (1984). R substituent is independently selected from hydride, Chemical Abstracts 100 121221q (1984). lower alkyl, phenyl, alkyl-substituted phenyl, cyclopen Chemical Abstracts 86 89943t (1977). tadienyl, and alkyl-substituted cyclopentadienyl, and M Ashe, et al., Preparation ... Dibismuthines, Organome is selected from elements of Groups 2B, 2A, 3A, 5A, tallics 1983, No. 2, p. 1865, Cols. 1-2 (synthesis of ben and 6A of the Periodic Table, except carbon, nitrogen, zyldimethylarsine). oxygen, and sulfur. The use of these compounds in Chemical Abstracts 60:14536e. chemical vapor deposition processes and methods for Chemical Abstracts 62:11405g (1965). synthesizing these compounds are also disclosed. CRC Handbook of Chemistry and Physics, 61st Ed. (1980–81), pp. 640-676. 43 Claims, 6 Drawing Figures U.S. Patent Mar. 29, 1988 Sheet of 4 4,734,514

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s 4,734,514 1. 2 operate the MOCVD apparatus, the carrier gas is intro HYDROCARBON-SUBSTITUTED ANALOGS OF duced into the bubbler under the surface of the organo PHOSPHINE AND ARSINE, PARTICULARLY FOR metallic compound. Rising bubbles of the carrier gas METAL, ORGANIC CHEMICAL WAPOR provide a large, constant contact surface and thus uni DEPOSITION formly vaporize the organometallic compound. The carrier gas and vapor collected in the headspace of the CROSS-REFERENCE TO RELATED bubbler are continuously directed to the deposition APPLICATION chamber. This application is a continuation-in-part of U.S. Ser. While it is possible to vaporize solid sources of ar No. 664,645, filed Oct. 25, 1984 by Hui, Melas, and O senic or phosphorus in a bubbler or furnace (see Bhat, Lorbeth, now pending. cited later), this way of providing arsenic orphosphorus has several disadvantages. First, when a III-V com TECHNICAL FIELD pound such as gallium arsenide is to be deposited the This invention relates to organometallic compounds Group III element (here, gallium) is conventionally comprising elements from Groups 2B, 2A, 3A, 5A, and 15 supplied from an organometallic compound such as 6A of the Periodic Table and mixed organic substituents trimethylgallium. The source of the Group V element selected from lower alkyl, hydride, phenyl, alkyl-sub should include hydride substituents so that monatomic stituted phenyl, cycloalkyl, and alkyl-substituted cyclo hydrogen will be formed when the hydride decomposes alkyl; particularly to analogs of arsine (AsH3) and phos in the deposition chamber. The monatomic hydrogen phine (PH3) in which one or two of the hydride substit 20 thus formed will react with the organic radicals (methyl uents is replaced by an organic substituent. This inven radicals, in the case of trimethylgallium) formed by tion also relates to metal organic chemical vapor depo decomposition of the Group V source in the deposition sition (MOCVD) processes employed in the semicon chamber to form gaseous waste (here, methane gas), ductor, optical, and optoelectronic industries for doping allowing the organic constituents to be removed from or coating a suitable substrate. 25 the site of deposition. For this reason, in prior practice BACKGROUND ART a large excess of Group V hydride (here, arsine) has MOCVD is a method for depositing dopants or thin been supplied to ensure thorough removal of organic metal or metal compound films on a silicon or other constituents. Elemental arsenic supplied to the deposi substrate. (In the present disclosure "metal' includes all 30 tion chamber would include no hydride substituents, of the elements of Groups 2B, 2A, 3A, 4A, 5A, and 6A and thus the resulting film would be contaminated with of the Periodic Table except carbon, nitrogen, oxygen, carbon from the Group III source. and sulfur.) The deposited films can be sources of dop Second, it is difficult to control the rate of vaporiza ing impurities which are driven into the substrate, or the tion of such solid sources because the surface area of a films themselves can have different electrical or optical 35 solid exposed to the carrier gas changes as vaporization properties than the substrate. These films are used in proceeds. In contrast, a liquid contained in a bubbler laser diodes, solar cells, photocathodes, field effect tran with substantially vertical walls presents the same sur sistors and other discrete devices, in fiber optic commu face area to the carrier gas so long as the flow and nications, microwave communications, digital audio bubble size of the carrier gas remains steady. Also, gases disc systems, and other advanced semiconductor, opti 40 (defined here as materials having a vapor pressure cal, and optoelectronic technologies. The properties of which exceeds the pressure within the bubbler at conve the film depend on the deposition conditions and the nient bubbler temperatures) are not preferred for chemical identity of the deposited film. MOCVD because gases cannot be evaporated at a uni A special advantage of MOCVD is that organometal form rate in a bubbler. For example, arsine and phos lic compounds can be found which have much higher 45 phine have been supplied as gases in pressurized cylin vapor pressures at moderate temperatures than the cor ders and metered directly into the deposition chamber. responding metals, and which decompose to release the Organometallic compounds for MOCVD desirably corresponding metals or form compounds thereof at the are liquids at bubbler pressure and at a temperature 200 to 800 degrees Celsius deposition temperatures between about -20 C. and about 40 C. Such con which should not be exceeded during fabrication. 50 pounds also should have a vapor pressure of at least Typical apparatus currently in use for MOCVD com about 1.0 torrs at the bubbler temperature, boil and prises a bubbler which contains a supply of the organo decompose at temperatures substantially exceeding the metallic compound chosen for a particular process, a bubbler temperature, and decompose readily at the reactor or deposition chamber which contains the sub temperature encountered in the deposition chamber. strate on which a film is to be deposited, a source of a 55 Another problem facing practitioners of MOCVD is carrier gas which is inert to the organometallic com that arsine and phosphine, commonly employed as pound in the bubbler and either inert or reactive to the sources of arsenic- and phosphorus-containing deposi compound in the deposition chamber, and optionally tion products, are highly toxic. They have been the sources of other reactants or dopants supplied to the subject of proposed and existing restrictive legislation. reaction chamber. The bubbler and contents are main 60 The triorganometallic compounds previously proposed tained at a constant and relatively low temperature to replace them, such as trimethylarsine, are far less which typically is above the melting point of the or toxic, but leave residual carbon decomposition products ganometallic compound but far below its decomposi in the deposited films. (See Bhat, “OMCVD Growth of tion temperature. The deposition chamber is typically GaAs and AlGaAs Using a Solid as a Source', Journal maintained at a much higher temperature, such as about 65 of Electronic Materials, Vol. 14, No. 4, 1985, pp.433-449. 200 to 800 degrees Celsius, particularly about 600 to 750 Kuech, et al. "Reduction of Background Doping in degrees Celsius, at which the organometallic compound Metal-Organic Vapor Phase Epitaxy of GaAs Using readily decomposes to release its constituent metal. To Triethyl Gallium at Low Reactor Pressures,' Appl. 4,734,514 3 Phys. Letters I, Oct. 15, 1985, not believed to be prior Triethylaluminum art, also may have relevance because it discloses that Triisobutylaluminum gallium arsenide films made with trimethylgallium and Trimethylaluminum arsine have more carbon residue than films made with Triphenylaluminum triethylgallium.) Also, some triorganometallic con 5 GALLIUM pounds of arsenic and phosphorus may not have vapor Triethylgallium pressures suitable for practicing MOCVD at a conve Trimethylgallium nient temperature. Thus, new compounds which are INDUM effective replacements for arsine and phosphine, but less Trimethylindium toxic, would be highly desirable. O Triethylindium The known organometallic compounds of elements in THALLUM Groups 2B, 2A, 3A, 5A, or 6A of the Periodic Table, Triethylthallium particularly bismuth, selenium, tellurium, beryllium, Trimethylthallium magnesium, or elements of Groups 2B or 3A of the PHOSPHORUS Periodic Table, are relatively few in number. For exam 15 Trimethylphosphine ple, the following compounds of these elements are all Triethylphosphine those lower alkyl, phenyl, alkyl-substituted phenyl, Tripropylphosphine cyclopentadienyl, or alkyl-substituted cyclopentadienyl Tributylphosphine organometallic compounds listed in the CRC Handbook Triphenylphosphine of Chemistry and Physics, 61st Edition, CRC Press, Inc., ARSENIC Boca Raton, Fla.: Dimethylarsine ZINC Methylarsine Di-n-butylzinc Phenylarsine Diethylzinc Tribenzylarsine Dimethylzinc 25 Trimethylarsine Diphenylzinc Triphenylarsine Di-n-propylzinc ANTIMONY Di-o-tolyzinc Pentamethylantimony CADMIUM Phenyldimethylantimony Dibutylcadmium 30 Tributylstibene Diethylcadmium Triethylantimony Diisobutylcadmium Trimethylantimony Dimethylcadmium Triphenylantimony Dipropylcadmium BSMUTH MERCURY 35 Methylbismuthine Dibenzylmercury Trimethylbismuthine Di-n-butylmercury Triethylbismuthine Diethylmercury Triphenylbismuthine Diisobutylmercury Tri-n-propylbismuth Diisopropylmercury SELENUM Dimethylmercury Diethylselenide Diphenylmercury TELLURIUM Dipropylmercury Dimethyltelluride Di-o-tolylmercury Diethyltelluride Di-m-tolylmercury 45 Some additional compounds disclosed in the prior art Di-p-tolylmercury include dicyclohexylphosphine (U.S. Pat. No. BERYLLIUM 3,547,881); various triorganophosphines (U.S. Ser. No. Di-n-butylberyllium 691,598, filed Jan. 15, 1985); and the mono- and dior Diethylberyllium ganic arsines and phosphines identified as prior art in Dimethylberyllium 50 Table II herein. See also Tzscach, et al., “Zur Synthese Dipropylberyllium der Dialkylamine Dialkylarsine. Sowie der Dialkyl MAGNESIUM arsine', Zeitschrift fur Anorganische und Allegemaine Dimethylmagnesium Chemie, Band 326, 1964 (pp. 280-287); and Horiguchu, Diphenylmagnesium et al., "Mass Spectrometric Study of Growth Reactions BORON 55 in Low Pressure CMVPE of GaAs by in situ Gas Sam Tribenzylboron pling,' presented at the 12th International Symposium Tri-n-butylboron on Gallium Arsenide and Related Compounds in Japan, Tri-t-butylboron 23-26 September, 1985 (this reference is not believed to Triethylboron be prior art). Triisobutylboron Because there are few organometallic compounds of Trimethylboron most of the listed elements, and particularly of alumi Triphenylboron num, gallium, indium, selenium, tellurium, beryllium, Tri-n-propylboron and magnesium, there often will be no compound of a Tri-sec-butylboron particular metal which is well suited to MOCVD. Fur Tri-p-tolylboron 65 thermore, most of the previously listed compounds Tri-p-xylylboron (with the exceptions of dimethylaluminum hydride, ALUMINUM diethylaluminum hydride, diisobutylaluminum hydride, Diisobutylaluminum hydride certain alkyl and dialkylarsines, phenylarsine, phenyl 4,734,514 5 6 dimethylantimony, and methylbismuthine) do not in clude more than one type of organic substituent on a SUMMARY OF THE INVENTION given molecule. Particularly for Group 2B, 2A, and 3A A first aspect of the invention is a genus of com elements of the Periodic Table it is difficult to select a pounds useful for metal organic chemical vapor deposi useful candidate having the necessary properties for 5 tion, comprising all the novel compounds defined by MOCVD. the molecular formula: Another factor complicates the selection of a work able organometallic compound for MOCVD: structur ally related organometallic compounds often do not x-y-y form homologous series. Many organometallic com O H pounds characteristically exist in only one form, for wherein N is either phosphorus or arsenic, H is hydride, example, as monomers, dimers, trimers, tetramers, or and X or Y are selected from hydrocarbons or hydride higher polymers. Structurally similar compounds often (but are not both hydride). These novel compounds are have different characteristic forms, and thus much dif 15 less toxic than the corresponding trihydride, but can ferent or inconsistent vapor pressures, melting points, scavenge hydrocarbons from the deposition chamber and decomposition temperatures. (unlike the corresponding triorganic substituted arsine As a particular case in point, consider the two known or phosphine). Most are in a convenient physical form compounds of indium-trimethylindium and triethylin (liquid and stable at some temperature between 0° C. dium. Both of these compounds have been used to de 20 and 150 C. and a pressure not greater than about one posit indium containing films. (See: 1. Manasevit and atmosphere) for being supplied from bubblers. Three Simpson, J. Electrochem. Soc., 118, C291 (1971); 120, additional advantages of many of these compounds are 135 (1973). 2. Bass, J. Crystal Growth, 31, 172 (1975). 3. that they are either nonpyrophoric or less pyrophoric Duchemin, et al., Paper 13, 7th Intern. Symp, on GaAs than the corresponding trihydrides; the pure liquids can and Related Compounds, Clayton, Md., September, 25 be stored under subatmospheric pressure and thus are 1978.) Though they are structurally similar, the respec not as prone to escaping as arsine or phosphine gases tive melting points, vapor pressures at 30 degrees Cel (which are stored under pressure greater than atmo sius and decomposition temperatures of these com spheric pressure); and they decompose at comparable or pounds are inconsistent with what would be expected of 3 lower temperatures than arsine orphosphine, so a lower homologs, as illustrated by Table I below: 0 deposition temperature and other comparable or milder deposition conditions can be successfully used. TABLE I A second aspect of the invention is a chemical vapor PROPERTY TRETHYLINEDIUM TRIMETHYLINDIUM deposition process in which compounds according to Melting Point -32 C. 88 C. the previous paragraph, or known mono- or diorganic Vapor Pressure 0.8 torrs 7.2 torrs 35 arsine or phosphine derivatives, are used as source ma at 30' C. terials. Temperature of 40' C. 150 C. Onset of A third aspect of the invention is a metal organic Decomposition chemical vapor deposition process comprising three steps. As the first step, first and second compounds are 40 selected, each having the formula: Trimethylindium is known to characteristically form a tetramer in the solid form and triethylindium is be MR lieved to characteristically form a loose liquid polymer structure at room temperature. This difference is be wherein x is an integer from 2 to 4 inclusive; each said lieved to underlie their inconsistent properties. 45 R substituent is independently selected from hydride, The preceding table illustrates that trimethylindium is lower alkyl, phenyl, alkyl-substituted phenyl, cyclopen a solid at temperatures employed in bubblers. Trime tadienyl, and alkyl-substituted cyclopentadienyl; and M thylindium has been vaporized by providing two bub is selected from elements of Groups 2B, 2A, 3A, 5A and blers in series to better control the amount of entrained 6A of the Periodic Table, except for carbon, nitrogen, 50 oxygen, and sulfur. The respective R substituents of the vapor. The apparatus necessary for this two bubbler first and second compounds are different, and prefera procedure is more expensive and complex, and yet pro bly mutually exclusive. All the R groups of the first vides less control of the partial pressure of trimethylin compound can be the same, and all the R groups of the dium, than apparatus used to vaporize a liquid from a second compound can be the same. As the second step, single bubbler. Triethylindium has an even lower vapor 55 a composite compound is made by any process. The pressure at 30 degrees Celsius than trimethylindium, composite compound also has the formula MRx, is dif and is also less thermally and chemically stable than ferent than the first and second compounds, and has at trimethylindium. Triethylindium starts to decompose to least one R substituent possessed by the first compound indium at 40 degrees Celsius, and at an even lower and at least one different R substituent possessed by the temperature in the presence of hydrogen-the typical second compound. The composite compound differs carrier gas. The vaporization of triethylindium thus from the first and second compounds as to at least one must take place at a temperature approaching its de property selected from decomposition temperature, composition temperature, and even then the deposition vapor pressure, and melting point. As the third and final rate is undesirably low. The lack of homology in these step, the composite compound is employed for metal indium compounds and the small number of known 65 organic chemical vapor deposition in apparatus com indium compounds have prevented those of ordinary prising a deposition chamber maintained at a tempera skill in the art from selecting an optimal compound for ture, between the melting point and decomposition indium MOCVD. temperature of the composite compound, at which the 4,734,514 7 8 composite compound has a vapor pressure which is useful for a particular deposition process. The apparatus TABLE II-continued further comprises a deposition chamber maintained at a Species N X Y 27 arsenic methyl neopentyl temperature at least as high as the decomposition tem 28 arsenic methyl cyclopentadienyl perature of the composite compound. Practice of this 5 29 arsenic methyl phenyl process allows one to tailor the molecular structure of 30 arsenic ethyl ethyl an organometallic compound of a desired metal to fit 31 arsenic ethyl n-propyl the required specifications of vapor pressure, melting 32 arsenic ethyl i-propyl 33 arsenic ethyl n-butyl point, boiling point and decomposition temperature 34 arsenic ethyl s-butyl which are necessary for successful or optimal practice O 35 arsenic ethyl i-butyl of MOCVD. 36 arsenic ethyl t-butyl 37 arsenic ethyl n-pentyl BRIEF DESCRIPTION OF DRAWINGS 38 arsenic ethyi i-penty 39 arsenic ethyl t-pentyl FIG. 1 is an infrared absorption spectrum of dime 40 arsenic ethyl neopenityl thylethylindium. 15 4. arsenic ethyl cyclopentadienyl 42 arsenic ethyl phenyl FIG. 2 is a proton nuclear magnetic resonance spec 43 arsenic n-propyl n-propyl trum of dimethylethylindium. 44 arsenic n-propyl i-propyl FIG. 3 is an infrared absorption spectrum of diethyl 45 arsenic n-propyl n-butyl methylindium. 46 arsenic n-propyl s-butyl 47 arsenic n-propyl i-butyl FIG. 4 is a proton nuclear magnetic resonance spec 48 arsenic n-propyl t-butyl trum of diethylmethylindium. 49 arsenic n-propyl n-pentyi FIG. 5 is a proton nuclear magnetic resonance spec 50 arsenic n-propyl i-pentyl trum of trimethylindium, a prior art compound. 5 arsenic n-propyl t-pentyl FIG. 6 is a proton nuclear magnetic resonance spec 52 arsenic n-propyl neopentyl 25 53 arsenic n-propyl cyclopentadienyl trum of triethylindium, a prior art compound. 54 arsenic n-propyl phenyl 55 arsenic i-propyl i-propyl DESCRIPTION OF PREFERRED 56 arsenic i-propyl n-butyl EMBODIMENTS 57 arsenic i-propyl s-butyl 58 arsenic i-propyl i-butyl The novel arsenic and phosphorus compounds of the 59 arsenic i-propyl t-butyl present invention have the formula: 30 60 arsenic i-propyl n-pentyl 61 arsenic i-propyl i-penty 62 arsenic i-propyl t-pentyl 63 arsenic i-propyl neopenityl x-y-y 64 arsenic i-propyl cyclopentadienyi H 65 arsenic i-propyl phenyl 35 66 arsenic n-butyl n-butyl wherein N is arsenic orphosphorus; H is hydride; Xand 67 arsenic n-butyl s-butyl 68 arsenic n-butyl i-butyl Y are selected from alkyl having from 1 to 5 carbon 69 arsenic n-butyl t-butyl atoms, aryl, and cycloalkyl; but not both X and Y are 70 arsenic n-butyl n-pentyl hydride and previously known compounds are ex 7 arsenic n-buty i-pentyl 72 arsenic n-butyl t-penty cluded. These compounds are exemplified by Table II, 73 arsenic n-buty neopentyl listing all arsenic and phosphorus compounds in which 74 arsenic n-buty cyclopentadienyl X and Y are independently selected from hydride, alkyl 75 arsenic n-butyl phenyl having from 1 to 5 carbon atoms, cyclopentadienyl, and 76 arsenic s-butyl s-butyl phenyl. 77 arsenic s-butyl i-buty 45 78 arsenic s-butyl t-butyl TABLE II 79 arsenic s-buty n-pentyl 80 arsenic s-buty i-pentyl Species N X Y 81 arsenic s-butyl t-pentyl arsenic hydride hydride 82 arsenic s-butyl neopenty 2 arsenic hydride methyl 83 arsenic s-butyl cyclopentadienyl 3* arsenic hydride ethyi 84 arsenic s-butyl phenyl 4 arsenic hydride n-propyl 50 85 arsenic i-butyl i-butyl 5 arsenic hydride i-propyi 86 arsenic i-butyl t-butyl 6 arsenic hydride n-butyl 87 arsenic i-butyl n-penty 7 arsenic hydride s-butyl 88 arsenic i-butyl i-penty 8 arsenic hydride i-butyl 89 arsenic i-butyl t-pentyl 9 arsenic hydride t-butyl 90 arsenic i-butyl neopenityl O arsenic hydride n-pentyl 55 91 arsenic i-butyl cyclopentadienyl arsenic hydride i-pentyl 92 arsenic i-butyl phenyl 2 arsenic hydride t-penty 93 arsenic t-buty t-buty 3 arsenic hydride neopenty 94 arsenic t-butyl n-penty 14 arsenic hydride cyclopentadienyl 95 arsenic t-butyl i-pentyl 15 arsenic hydride phenyl 96 arsenic t-buty t-penty! 16 arsenic methyl methyl 97 arsenic t-butyl neopenityl 17 arsenic methyl ethyi 98 arsenic t-butyl cyclopentadienyl 18" arsenic methyl n-propyl 99 arsenic t-butyl phenyl 19 arsenic methyl i-propyl 100 arsenic n-pentyl n-pentyl 20 arsenic methyl n-butyl 101 arsenic n-pentyl i-pentyl 21 arsenic methyl s-butyl 02 arsenic n-pentyl t-penty 22 arsenic methyl i-butyl 65 103 arsenic n-pentyl neopenityl 23 arsenic methyl t-butyl 04 arsenic n-pentyl cyclopentadienyl 24 arsenic methyl n-pentyl 105 arsenic n-penty phenyl 25 arsenic methyl i-pentyl 06 arsenic i-pentyl i-pentyl 26 arsenic methyl t-pentyl 07 arsenic i-pentyl t-pentyl 4,734,514 9 10 TABLE II-continued TABLE II-continued Species N X Y Species N X Y 108 arsenic i-penty neopenty 89 phosphorus n-butyl t-butyl 109 arsenic i-pentyl cyclopentadienyl 5 90 phosphorus n-butyl n-pentyl 110 arsenic i-penty phenyl 9. phosphorus n-butyl i-penty! 1. arsenic t-penty t-penty 92 phosphorus n-butyl t-pentyl 112 arsenic t-penty neopenityl 93 phosphorus n-butyl neopenityl 113 arsenic t-penty cyclopentadienyl 194 phosphorus n-butyl cyclopentadienyl 14 arsenic t-penty phenyl 195 phosphorus n-butyl phenyl 5 arsenic neopenityl neopenty 196 phosphorus s-buty s-butyl 116 arsenic neopenityl cyclopentadienyl O 197 phosphorus s-butyl i-butyl 117 arsenic neopenty phenyl 198 phosphorus s-butyl t-butyl 118 arsenic cyclopentadienyl cyclopentadienyl 99. phosphorus s-butyl n-pentyl 119 arsenic cyclopentadienyl phenyl 200 phosphorus s-butyl i-penty! 120 arsenic phenyl phenyl 201 phosphorus s-butyl t-pentyl 121' phosphorus hydride hydride 202 phosphorus s-buty neopenityl 122 phosphorus hydride methyl 15 203 phosphorus s-butyl cyclopentadienyl 123 phosphorus hydride ethyl 204 phosphorus s-butyl phenyl 124 phosphorus hydride n-propyl 205 phosphorus i-butyl i-butyl 125° phosphorus hydride i-propyl 206 phosphorus i-butyl t-butyl 126 phosphorus hydride n-butyl 2O7 phosphorus i-butyl n-penty 127 phosphorus hydride s-butyl 208 phosphorus i-butyl i-pentyl 128° phosphorus hydride i-butyl 2O 209 phosphorus i-butyl t-pentyl 129 phosphorus hydride t-butyl 210 phosphorus i-butyl neopenityl 130 phosphorus hydride n-penty 2 phosphorus i-butyl cyclopentadienyl 131 phosphorus hydride i-pentyl 22 phosphorus i-butyl phenyl E32 phosphorus hydride t-pentyl 213 phosphorus t-butyl t-butyl 133 phosphorus hydride neopenty 214 phosphorus t-buty n-penty 134 phosphorus hydride cyclopentadienyl 25 215 phosphorus t-butyl i-pentyl 135° phosphorus hydride phenyl 216 phosphorus t-butyl t-pentyl 136 phosphorus methyl methyl 217 phosphorus t-butyl neopentyi 137 phosphorus methyl ethyl 28 phosphorus t-butyl cyclopentadienyi 138 phosphorus methyl n-propyl 219 phosphorus t-butyl phenyl 39 phosphorus methyl i-propyl 220 phosphorus n-pentyl n-pentyl 140° phosphorus methyl n-butyl 30 221 phosphorus n-pentyl i-pentyl 14 phosphorus methyl s-butyl 222 phosphorus n-pentyl t-pentyl 42 phosphorus methyl i-butyl 223 phosphorus n-pentyl neopenityl 143 phosphorus methyl t-butyl 224 phosphorus n-pentyl cyclopentadienyl 144 phosphorus methyl n-pentyl 225 phosphorus n-pentyl phenyl 145 phosphorus methyl i-pentyl 226 phosphorus i-pentyl i-pentyl 146 phosphorus methyl t-penty 227 phosphorus i-penty t-penty 147 phosphorus methyl neopenty 35 228 phosphorus i-pentyl neopenityl 48 phosphorus methyl cyclopentadienyl 229 phosphorus i-pentyl cyclopentadienyl 49 phosphorus methyi phenyl 230 phosphorus i-penty phenyl 150° phosphorus ethyl ethyl 231 phosphorus t-penty t-penty 15 phosphorus ethyl n-propyl 232 phosphorus t-penty neopentyl 152 phosphorus ethyl i-propyl 233 phosphorus t-pentyl cyclopentadienyl 153 phosphorus ethyl n-buty 40 154 phosphorus ethyl s-butyl 234 phosphorus t-penty phenyi 155 phosphorus ethyl i-buty 23S phosphorus neopenityl neopenityl 56 phosphorus ethyl t-butyl 236 phosphorus neopenityl cyclopentadienyi 157 phosphorus ethyl n-pentyl 237 phosphorus neopentyl phenyl 158 phosphorus ethyl i-pentyl 238 phosphorus cyclopentadienyl cyclopentadienyl 159 phosphorus ethyi t-pentyl 45 239 phosphorus cyclopentadienyl phenyl 160 phosphorus ethyl neopenityl 240 phosphorus phenyl phenyl 161 phosphorus ethyl cyclopentadienyl 162 phosphorus ethyl phenyl 163 phosphorus n-propyl n-propyl 35 of the 240 compounds named in the Table II (spe 164 phosphorus n-propyl i-propyl cies 1-6, 9, 15-18, 29, 30, 43, 55, 66, 120-126, 128, 129, 165 phosphorus n-propyl n-butyl 50 130, 135, 136, 137, 138, 140, 150, 186, 213, and 240) are 166 phosphorus n-propyl s-buty 167 phosphorus n-propyl i-butyl not novel, but the remaining species are. (Hereinafter, if 168 phosphorus n-propyl t-butyl no particular isomer of an alkyl group is specified, any 169 phosphorus n-propyl n-penty isomer is intended.) 170 phosphorus n-propyl i-pentyl The preparation of the arsenic compounds is exempli 171 phosphorus n-propyl t-penty 172 phosphorus n-propyl neopenty 55 fied in Example 1 and by Doak, et al., Organometallic 173 phosphorus n-propyl cyclopentadienyl Compounds of Arsenic, Antimony, and Bismuth (New 74 phosphorus n-propyl phenyl York: Wiley-Interscience), pp 120-127; and Hagihara, 175 phosphorus i-propyl i-propyl et al., Handbook of Organometallic Compounds (New 76 phosphorus i-propyl n-butyl 177 phosphorus i-propyl s-butyl York: W. A. Benjamin, Inc.) 1968, pp. 720-726. 178 phosphorus i-propyl i-butyl 60 The preparation of the phosphorus compounds is 179 phosphorus i-propyl t-butyl exemplified by diethylphosphine, prepared as follows: 18O phosphorus i-propyl n-pentyl 181 phosphorus i-propyl i-pentyl 182 phosphorus i-propyl t-penty 183 phosphorus i-propyl neopentyl 2E-R-RE: + 3LiAlH4 + 12H2O - Ge. 184 phosphorus i-propyl cyclopentadienyl 65 S S 185 phosphorus i-propyl phenyl 186 phosphorus n-butyl n-butyl 87 phosphorus n-buty s-butyl 188 phosphorus n-buty i-butyl 4,734,514 11 12 (Literature reference: Inorganic Chemistry 1962, 1(3), Looking more closely at the step of selecting first and 471.) Other substituted phosphines can be prepared by second compounds, the compounds from which the substituting X and Y moieties from Table II for the two selection is made have the formula ethyl groups attached to phosphorus in the starting material used in the above reaction. Preparations for 5 MR certain organophosphines found useful herein, but not their utility, are also disclosed in Hagihara, et al., Hand The M substituents are selected from elements of book of Organometallic Compounds (New York: W. A. Groups 2B, 2A, 3A, 5A, and 6A of the Periodic Table, Benjamin, Inc.), 1968, pp. 560, 566, 571, 574, 579, and except for Carbon, Nitrogen, Oxygen, and Sulfur. Since 580; and Kosolapoff, et al., Organic Phosphorus Com 10 in the usual chemical vapor deposition process a partic pounds, Vol. 1 (New York: Wiley-Interscience), pp. ular element has been selected for deposition, usually 4-11 and 16-27. the M constituents of the first and second compounds Hybrid organic analogs of arsine and phosphine (in will be the same. However, the process is not limited by which X and Y are different) also can be produced by this consideration. R substituents contemplated for use mixing two analogs, each one including one of the re 5 in the novel compounds include hydride, lower alkyl, spective substituents of the hybrid; by reacting a halo phenyl, alkyl-substituted phenyl, cyclopentadienyl, and gen substituted organometallic compound with an al alkyl-substituted cyclopentadienyl. Lower alkyl is de kylating or arylating agent to add an unlike substituent; fined herein as a substituent having from one to four by reacting the metal for which an organometallic hy carbon atoms, and specifically includes methyl, ethyl, brid compound is desired with mixtures of organic ha 20 n-propyl, isopropyl, n-butyl, s-butyl, isobutyl, and t lides; by substituting a more active metal for a less ac butyl. Alkyl-substituted phenyl as defined herein in tive metal in an organometallic hybrid compound of the cludes alkyl-substituted phenyl and phenyl-substituted less active metal; or by other means. These reactions are alkyl, alkyl being lower alkyl as exemplified above. similar to the methods set forth later for preparing hy Specific substituents contemplated within the meaning brid organometallic compounds. 25 of alkyl-substituted phenyl are as follows: benzyl; tolyl As indicated previously, the above novel compounds, in ortho, meta, or para positions with respect to the as well as known species in Table II, have utility as metal; xylyl, including orientations in which the methyl reactants in MOCVD. Preferred reactants for this util substituents are ortho with respect to each other and ity have a melting point of less than about 30 degrees respectively ortho and meta or meta and para with Celsius, have a vapor pressure of at least 1.0 torr at a 30 respect to the metal, or if the methyl substituents are temperature within the bubbler temperature range of meta, situations in which the methyl substituents are from about minus 20 degrees Celsius to about 40 de respectively ortho and ortho, or ortho and para, or meta grees Celsius, are stable at the indicated bubbler temper and meta with respect to the metal atom, and if the atures but readily decompose at a deposition chamber 35 methyl substituents are para, the situation in which the temperature of from about 200 to about 800 degrees methyl substituents are ortho and meta to the metal Celsius, preferably from about 550 to about 700 degrees substituent of the phenyl; ethylphenyi, isopropylphenyl, Celsius, and are inert at bubbler temperatures with re butylphenyl, isobutylphenyl, t-butylphenyl, these sub spect to at least one carrier gas such as hydrogen, nitro stituents being in ortho, meta, or para relation to the gen, or helium. metal atom; and any other phenyl having one or more The present compounds also have utility for the prep 40 of the alkyl substituents previously defined. Alkyl-sub aration of other such compounds within the scope of stituted cyclopentadienyl as defined herein includes the present invention. For example, a listed compound alkyl-substituted cyclopentadienyl and cyclopentadie which does not have a desirable decomposition temper nyl substituted alkyl, alkyl being lower alkyl as exempli ature may be reacted with another organometallic com 45 fied above. Specific substituents contemplated within pound to produce a new hybrid. the meaning of alkyl-substituted cyclopentadienyl are as The ultimate utility of these compounds, employed in follows: methylcyclopentadienyl, 4-(cyclopentadienyl)- MOCVD, is to provide dopants or coatings of the ar n-butyl, pentamethylcyclopentadienyl, and cyclopenta senic or phosphorus oxides, nitrides, III-V compounds, dienyl substituted by up to six like or different lower and so forth. 50 alkyl groups and linked directly or by one of the lower alkyl groups to the selected metal atom. All R substitu PROCESS FOR SELECTING AND USING ents on the first compound can be alike or different, as HYBRID ORGANOMETALLIC COMPOUNDS can all R substituents on the second compound. 'x' is FORMOCVD an integer from 2 to 4 inclusive, depending upon the A third aspect of the present invention is a process for 55 valence of the chosen metal. The process is particularly selecting particular hybrid organometallic compounds useful when neither the first compound nor the second of Group 2B, 2A, 3A, 5A, and 6A elements which are compound has an optimal melting point, vapor pres useful in metal organic chemical vapor deposition pro sure, or decomposition temperature for use in CSSES MOCVD. First and second compounds meeting this The present process, characterized as an MOCVD definition are trimethylindium and triethylindium, process, comprises the steps of selecting first and second whose melting points, volatility, and decomposition compounds, each having the formula MR as further temperatures are set forth above in Table I. defined below, making a hybrid compound having at Other examples of first and second compounds useful least one substituent in common with the first com in practicing the present invention can be found in the pound and at least one substituent in common with the 65 list of known homosubstituted and hybrid organometal second compound, and employing the hybrid com lic compounds in the “BACKGROUND ART' section pound for metal organic chemical vapor deposition in set forth previously; and in the species list in the de apparatus further specified below. scription of arsenic and phosphorus compounds. 4,734,514 13 14 Once first and second compounds have been selected, Other methods ordinarily used in organometallic the next step is to make a composite compound having synthesis, such as those discussed on pages 345-348 and at least one R substituent possessed by the first com 365-366 of Roberts and Caserio, Basic Principles of Or pound and at least one different R substituent possessed ganic Chemistry, W. A Benjamin Inc. (New York: 1964) by the second compound. Although one manner of 5 can also be adapted to synthesize the hybrid organome synthesizing the composite compound is by mixing the tallic compounds defined herein. first and second compounds, the present process is not The composite compound, however made, should limited to a particular method of synthesis. The other differ from each of the first and second compounds as to synthetic methods described below, or methods not at least one property selected from decomposition tem specifically disclosed herein, can also be used within the 10 perature, vapor pressure at a particular temperature scope of the present process invention. To practice the suitable for a bubbler, and melting point. By differing in mixing method described in the preceding paragraph, respect to at least one of these properties, the composite the first and second compounds are mixed together and compound will be useful for MOCVD under different allowed to equilibrate at a temperature below the lower process conditions than the first and second com of the boiling points of the reactants and products, pref 15 pounds. When one of the first and second compounds erably from 0-30 Celsius. A nonreactive solvent such has a property such as melting point which is too low as benzene, hexane, ether, tetrahydrofuran, etc. is op for a conventional MOCVD process and the other com tional. The result of this exchange reaction will typi pound has a corresponding property which is too high cally be a major proportion of a hybrid organometallic for MOCVD, the composite compound defined herein compound according to the invention, in which the 20 may have a corresponding property between those of several R substituents are present in roughly the same the first and second compounds or may have a surpris proportions as in the reaction mixture containing the ingly different value of the corresponding property. first and second reactants. Minor proportions of the Examples of the composite compounds within the reactants and of other organometallic products may scope of the second step of the process include the also be present. The desired product can be isolated by 25 generic class and species set forth previously for the distillation, crystallization, or other well known pro compound invention, as well as the previously men cesses. Alternatively, the product mixture can be used. tioned hybrid organometallic compounds known to the for MOCVD without isolating a pure hybrid product. art. Still further examples of such compounds are the The following equations illustrate reactions of this type following: in which stoichiometric proportions of the reactants 30 dimethylethylantimony provide a major proportion of the indicated product: dimethylbutylphosphine dimethylphenylarsine The above species can be made in the same manner as other hybrid organometallic compounds disclosed herein, such as by respectively mixing and equilibrating trimethylantimony and triethylantimony; trimethyl In a second synthetic method, a halogenated organo phosphine and tributylphosphine; and trimethylarsine metallic compound having one of the desired alkyl, and triphenylarsine. phenyl, alkyl-substituted phenyl, cyclopentadienyl, or As a final step, the composite compound is employed alkyl-substituted cyclopentadienyl substituents is re for MOCVD in apparatus comprising a bubbler or acted with an alkylating or arylating agent. The alkyl or equivalent apparatus maintained at a temperature be aryl group of the alkylating or arylating agent then tween the melting point and decomposition temperature replaces the halogen substituent of the organometallic of the composite compound. The desired composite compound. Typical alkylating agents for use herein compound will have a vapor pressure at this tempera include such materials as methyllithium, ethylmag 45 ture of at least 1.0 torrs, and thus will be useful for nesium bromide, or lithium aluminum hydride. Exam deposition. The MOCVD apparatus used in this step ples of these synthetic reactions are set forth in the three further comprises a deposition chamber maintained at a following equations: temperature at least as high as the decomposition tem perature of the composite compound, triggering the breakdown of the composite organometallic compound CH32nBr--C2H5MgBr-CH3C2H52n--MgBr2 to release its constituent metal. The present hybrid organometallic compounds have (CH3)3Al--LiAlH4->(CH3)2AlH--LiAlH3(CH3) an advantage over any nonazeotropic mixture for use in MOCVD, as any nonazeotropic mixture will be frac The reaction of metals with mixtures of organic halides 55 tionated by the carrier gas in a manner analogous to gas to produce hybrid organometallic compounds is useful, liquid chromatography. and is illustrated by the following reaction: In the above process invention, the preferred com pounds are selected from: CH3Br--C2H5Br--2Se-CH3C2H5Se-i-SeBr2 methylethylzinc: 60 methylbenzyltelluride; A metal displacement reaction can be used, and is dimethylethylboron; exemplified by the following reaction: dimethylethylthallium; methylxylylselenium; methylphenylgallium hydride; 65 ditolylgallium hydride; In the above reaction, it will be appreciated that the metal of the organometallic reactant must be a less ac and compounds having the formula: tive metal than the substituting metal. MR 4,734,514 15 16 with 5 grams (0.13 mol) of lithium aluminum hydride wherein X is an integer from 2 to 4 inclusive, each said and 200 ml. of diethyl ether. The contents of the drop R substituent is independently selected from hydride, ping funnel are then added slowly to the reaction flask lower alkyl, phenyl, alkyl-substituted phenyl, cyclopen while the contents are stirred vigorously. After the tadienyl, and alkyl-substituted cyclopentadienyl, at least 5 dropping funnel has been emptied, it is charged with 20 two of said R substituents are different, and M is an ml. of degassed water. The water is then added slowly element selected from cadmium, aluminum, gallium, with stirring to the reaction mixture. The contents of indium, and bismuth, but excluding aluminum, bismuth, the three-neck reaction flask are transferred under a and gallium if any R is hydride. The selected compound nitrogen atmosphere to a one liter separatory funnel and is placed in a bubbler and used as a source of metal 10 the aqueous layer is removed and discarded. The ether constituent M in a chemical vapor deposition process. layer is transferred into a 500 ml. flask containing 200 g EXAMPLES of anhydrous sodium sulfate and the mixture is stirred overnight and then filtered. Diethyl ether is removed The following examples are provided to further ex from the filtrate by distillation at atmospheric pressure. emplify the present compound and process inventions. 15 The final product, diethylarsine, is isolated by atmo The examples do not limit the scope of the invention, spheric pressure distillation at 100-110' C. as a clear, which is defined by the claims found at the end of the colorless liquid (4.6 g., 38% overall yield based on ar specification. All manipulations described are per senic trichloride). formed under a purified nitrogen atmosphere or under The other di-substituted arsines of Table II are syn vacuum, unless the contrary is stated. 20 thesized by substituting for the two moles of ethylmag EXAMPLE 1. nesium bromide one mole of an alkylmagnesium bro mide in which the alkyl group is the X substituent in SYNTHESIS OF DIETHYLARSINE Table II, and one mole of an alkylmagnesium bromide First, diethylaminodichlorarsine is synthesized. A in which the alkyl group is the Y substituent in Table II. three-neck, one liter flaskis equipped with a mechanical 25 stirrer, condenser and dropping funnel, and charged EXAMPLE 2 with 164 g (0.905 mol) of arsenic trichloride. The ar SYNTHESIS OF DIMETHYLETHYLINEDIUM senic trichloride is dissolved in 300 ml of diethyl ether. Diethylamine (132 g, 1.81 mol) is added to the flask 3.00 ml, of triethylindium (3.78 g., 0.0187 mol) was (through the dropping funnel), and the contents of the 30 added to 5.988 g. (0.0374 mol) of trimethylindium in a flask are stirred for two hours at room temperature. The 50 ml. flask in a glove bag under an argon atmosphere. contents are then filtered to remove the diethylamine The reagents were stirred at room temperature over hydrochloride byproduct. The filtrate is used directly in night. Reaction was essentially complete when all of the the next reaction. trimethylindium was fully reacted, leaving no residual Next, diethylaminodiethylarsine is prepared. A simi 35 solids. The resulting clear liquid was then distilled larly equipped three-neck, two liter flask is arranged so under full vacuum (about 1.5 torrs pressure). Some of the dropping funnel aims into the flask, rather than the resulting dimethylethylindium distilled over at dropping its contents down the wall of the flask. The room temperature, or about 23 degrees Celsius. Gentle flask is charged with the filtrate from the previous reac heating caused the rest to come over at 25 degrees Cel tion (diethylaminodichlorarsine and diethyl ether). Two sius, this temperature being measured at the distillation moles of ethylmagnesium bromide (3 molar solution in head. The resulting product had a melting point of diethyl ether) are added dropwise to the reaction flask about 5 to 7 degrees Celsius and a boiling point of through the dropping funnel and the contents are 23-25 C. at 1.5 torrs, which is unexpectedly different stirred overnight at room temperature. The reaction than the respective melting points and boiling points of mixture is filtered and the filter cake is washed with 45 trimethylindium and triethylindium. Proton nuclear diethyl ether. The filtrate is used directly in the next magnetic resonance and infrared spectra were taken, reaction. and are presented as FIGS. 1 and 2 forming a part of Third, diethylchloroarsine is prepared. A three-neck, this specification. For comparison, the NMR spectra of two liter flask is equipped with a fritted gas inlet tube, trimethylindium and triethylindium are presented as mechanical stirrer, and condenser and charged with the 50 FIGS. 5 and 6. The infrared spectrum is not believed to filtrate from the previous reaction (diethylaminodiethy distinguish the product compound, but the NMR spec larsine and diethyl ether). Hydrogen chloride gas is trum of dimethylethylindium is characterized by peaks bubbled through the solution with stirring at room tem at delta -- 1.27 (triplet representing ethyl); +0.37 (quar perature until a precipitate forms and then redissolves tet representing ethyl); and -0.36 (singlet representing (10-30 minutes). Excess HCl is distilled out of the two 55 liter flask along with diethyl ether at atmospheric pres methyl). Integration of the areas under the peaks pro sure. A precipitate of diethylamine hydrochloride reap vides the ratio of methyl to ethyl groups, which is 2:1. pears. The mixture is filtered to remove the by-product, EXAMPLE 3 diethylamine hydrochloride. The filtrate (diethyl chloroarsine and diethyl ether) is used directly in the SYNTHESIS OF DIETHYLMETHYLINDIUM next reaction. 5.00 ml. (6.30 g., 0.0312 mol.) of triethylindium was Fourth, diethylarsine is prepared. The filtrate from added to 2.495 g. (0.0156 mol.) of trimethylindium in a the previous reaction (diethylchloroarsine and diethyl 50 ml. flask in a glove bag containing an argon atmo ether, total weight 98 g) is transferred under a nitrogen sphere. The mixture was stirred overnight and then atmosphere into a 250 ml dropping funnel. A three 65 distilled at 33 to 35 degrees Celsius under full vacuum as neck, one liter flask is equipped with a magnetic stirrer, previously defined. The distillate was a clear, colorless condenser, and the dropping funnel containing the fil liquid. NMR and IR spectra were taken, and are pro trate from the previous reaction. The flask is charged vided as FIGS. 3 and 4 herein. The NMR is character 4,734,514 17 18 ized by peaks at delta values of -- 1.28 (triplet ethyl); chamber, where they break down and react to form a --0.39 (quartet ethyl); and -0.39 (singlet methyl). An gallium arsenide film on said substrate. The film is ana integration of the areas under the peaks shows a ratio of lyzed for carbon content and found to contain a reduced ethyl to methyl of 1.94:1. The melting point was found amount thereof, compared to the carbon content of a to be below about 0 degrees Celsius, as the product 5 gallium arsenide film made under similar conditions, failed to solidify when the container was placed in ice using trimethylgallium and arsine as reactants. Water. EXAMPLE 7 EXAMPLE 4 MOCVD PROCESS PROPERTIES OF TRIMETHYLINDUMAND O Methyldiethylindium prepared as described previ TRIETHYLINDIUM (PRIOR ART) ously is placed in a bubbler and suitably interconnected FIG. 5 is the NMR spectrum of trimethylindium, with a source of hydrogen gas and a deposition cham characterized by a singlet methyl peak at a delta value ber. The chamber is also supplied with phosphine gas. of -0.20. The melting point of trimethylindium is 88 The bubbler is maintained at 20 degrees Celsius using a degrees Celsius. 15 suitable heat source, the deposition chamber is main FIG. 6 is the NMR spectrum of triethylindium, char tained at 650 degrees Celsius, and an indium phosphide acterized by peaks at delta values of +1.24 (triplet substrate is supported within the deposition chamber. ethyl) and +0.40 (quartet ethyl). The melting point of The entraining hydrogen is delivered at 100 cubic centi triethylindium is -32 degrees Celsius. meters per minute (at standard temperature and pres 20 sure). The partial pressure of hydrogen in the deposition EXAMPLE 5 chamber is atmospheric pressure, and the partial pres SYNTHESIS OF OTHER HYBRID sure of methyldiethylindium is about 10 torrs, the par ORGANOMETALLIC COMPOUNDS tial pressure of phosphine being atmospheric pressure. Reactants 1 and 2 listed in Table III below are mixed 25 After about 30 minutes of deposition, a coating of in in a flaskin a glove bag under an argon atmosphere and dium phosphide approximately 2 microns thick, uni form in composition and thickness, is found to be depos stilled overnight. The hydrocarbon substituents of the ited on the substrate. reactants redistribute, thereby forming a mixture of What is claimed is: materials which includes the product listed in Table III. 1. A compound having the structure:

Diethylarsine, prepared as described previously, is placed in a bubbler and suitably interconnected with a wherein H is hydride and the respective identities of N, source of hydrogen gas and a deposition chamber. X, and Y are selected from the following table of spe Trimethylgallium is placed in a second bubbler and cies: suitably interconnected with a source of hydrogen gas 65 and the same deposition chamber. A substrate is placed within the deposition chamber. Vapors of diethylarsine N X Y and trimethylgallium are transported into the deposition arsenic hydride s-butyl 4,734,514 19 20 -continued -continued N X Y N X Y arsenic hydride i-butyl arsenic n-penty n-pentyl arsenic hydride n-pentyi 5 arsenic n-pentyl i-penty arsenic hydride i-pentyl arsenic n-pentyl t-pentyl arsenic hydride t-pentyl arsenic n-pentyl neopenityi arsenic hydride neopenty arsenic n-penty cyclopentadienyl arsenic hydride cyclopentadienyl arsenic n-penty phenyl arsenic methyl i-propyl arsenic i-penty i-penty arsenic methyl n-butyl O arsenic i-penty t-pentyl arsenic methyl s-butyl arsenic i-penty neopenty arsenic methyl i-butyl arsenic i-pentyl cyclopentadienyl arsenic methyl t-butyl arsenic i-pentyl phenyl arsenic methyl n-penty arsenic t-pentyl t-penty arsenic methyl i-penty arsenic t-pentyl neopentyl arsenic methyl t-pentyi arsenic t-penty cyclopentadienyl arsenic methyl neopenityl 5 arsenic t-penty phenyl arsenic methyl cyclopentadienyl arsenic neopenityl neopenty arsenic ethyl n-propyl arsenic neopenityl cyclopentadienyl arsenic ethyl i-propyl arsenic neopenityl phenyl arsenic ethyl n-butyl arsenic cyclopentadienyl cyclopentadienyl arsenic ethyl s-butyl arsenic cyclopentadienyl phenyl arsenic ethyl i-butyl 20 phosphorus hydride t-penty arsenic ethyl t-butyl phosphorus hydride neopenty arsenic ethyl n-pentyl phosphorus methyl s-butyl arsenic ethyl i-penty phosphorus methyl i-buty arsenic ethyl t-pentyl phosphorus methyl t-butyl arsenic ethyl neopenty phosphorus methyl n-penty arsenic ethyl cyclopentadienyl 25 phosphorus methyl i-pentyl arsenic ethyi phenyl phosphorus methyl t-penty arsenic in-propyl i-propyl phosphorus methyl neopentyl arsenic n-propyl n-buty phosphorus methyl cyclopentadienyl arsenic n-propyl s-butyl phosphorus ethyl n-propyl arsenic n-propyl i-butyl phosphorus ethyl i-propyl arsenic n-propyl t-butyl 30 phosphorus ethyl n-butyl arsenic n-propyl n-penty phosphorus ethyl s-butyl arsenic n-propy i-penty phosphorus ethyl i-butyl arsenic n-propyl t-penty phosphorus ethyl t-butyl arsenic n-propyl neopentyi phosphorus ethyl n-pentyl arsenic n-propyl cyclopentadienyl phosphorus ethyl i-pentyl arsenic n-propyl phenyl phosphorus ethyl t-pentyl arsenic i-propyl n-butyl 35 phosphorus ethyl neopentyl arsenic i-propyl s-butyl phosphorus ethyl cyclopentadienyl arsenic i-propyl i-butyl phosphorus n-propyl i-propyl arsenic i-propyl t-butyl phosphorus n-propyl n-butyl arsenic i-propyl n-penty phosphorus n-propyl s-butyl arsenic i-propyl i-pentyl phosphorus n-propyl i-butyl arsenic i-propy t-pentyi 40 phosphorus n-propyi t-butyl arsenic i-propyl neopenityl phosphorus n-propyl n-pentyl arsenic i-propyl cyclopentadienyl phosphorus n-propyl i-penty arsenic i-propyl phenyl phosphorus n-propyl t-pentyl arsenic n-butyl s-butyl phosphorus n-propyl neopenityl arsenic n-butyl i-butyl phosphorus n-propyl cyclopentadienyl arsenic n-butyl t-butyl 45 phosphorus n-propyl phenyl arsenic n-butyl n-pentyl phosphorus i-propyl n-butyl arsenic n-butyl i-pentyl phosphorus i-propyl s-butyl arsenic n-buty t-pentyl phosphorus i-propyl t-butyl arsenic n-butyl neopenty phosphorus i-propyl n-pentyl arsenic n-buty cyclopentadienyl phosphorus i-propyl i-pentyl arsenic n-butyl phenyl 50 phosphorus i-propyl t-pentyl arsenic s-buty s-butyl phosphorus i-propyl neopenityl arsenic s-butyl i-butyl phosphorus i-propyl cyclopentadienyl arsenic s-butyl t-butyl phosphorus i-propyl phenyl arsenic s-butyl n-penty phosphorus n-butyl s-butyl arsenic s-butyl i-pentyl phosphorus n-butyl i-butyl arsenic s-butyl t-penty phosphorus n-butyl t-butyl arsenic s-butyl neopenty 55 phosphorus n-butyl n-penty arsenic s-butyl cyclopentadienyl phosphorus n-butyl i-pentyl arsenic s-butyl phenyl phosphorus n-butyl t-pentyi arsenic i-butyl i-butyl phosphorus n-butyl neopenityl arsenic i-butyl t-butyl phosphorus n-butyl cyclopentadienyl arsenic i-butyl n-penty phosphorus s-butyl i-butyl arsenic i-butyl i-pentyl 60 phosphorus s-butyl t-butyl arsenic i-butyl t-penty phosphorus s-butyl n-pentyl arsenic i-butyl neopenityl phosphorus s-butyl i-pentyl arsenic i-butyl cyclopentadienyl phosphorus s-butyl t-pentyl arsenic i-butyl phenyl phosphorus s-butyl neopenityl arsenic t-butyl n-penty phosphorus s-butyl cyclopentadienyl arsenic t-butyl i-pentyl 65 phosphorus s-butyl phenyl arsenic t-butyl t-penty: phosphorus i-butyl t-butyl arsenic t-butyl neopentyl phosphorus i-butyl n-perityl arsenic t-butyl cyclopentadienyl phosphorus i-butyl i-penty arsenic t-butyl phenyl phosphorus i-butyl t-penty 4,734,514 21 22 17. The compound of claim 1, where N is arsenic, X -continued is propyl, Y is cyclopentadienyl. N X Y 18. The compound of claim 1, where N is arsenic, X phosphorus i-butyl neopenity is propyl, Y is phenyl. phosphorus i-butyl cyclopentadienyl 5 phosphorus i-butyl phenyl 19. The compound of claim 1, where N is arsenic, X phosphorus t-butyl n-pentyl is butyl, Y is isobutyl. phosphorus t-butyl t-pentyl 20. The compound of claim 1, where N is arsenic, X phosphorus t-butyl neopenityl is butyl, Y is sec-butyl. phosphorus t-butyl cyclopentadienyl 21. The compound of claim 1, where N is arsenic, X phosphorus n-pentyl n-pentyl 10 phosphorus n-pentyl i-pentyl is butyl, Y is pentyl. phosphorus n-pentyl t-pentyl 22. The compound of claim 1, where N is arsenic, X phosphorus n-pentyl neopenityl is butyl, Y is cyclopentadienyl. phosphorus n-penty cyclopentadienyl 23. The compound of claim 1, where N is arsenic, X phosphorus n-penty phenyl is butyl, Y is phenyl. phosphorus i-penty t-pentyl 15 phosphorus i-penty neopentyl 24. The compound of claim 1, where N is arsenic, X phosphorus i-pentyl cyclopentadienyl is pentyl, Y is pentyl. phosphorus i-pentyi phenyl 25. The compound of claim 1, where N is arsenic, X phosphorus t-pentyl t-pentyl is pentyl, Y is cyclopentadienyl. phosphorus t-pentyl neopentyl phosphorus t-pentyl cyclopentadienyl 2O 26. The compound of claim 1, where N is arsenic, X phosphorus t-pentyl phenyl is pentyl, Y is phenyl. phosphorus neopenty neopenityl 27. The compound of claim 1, where N is arsenic, X phosphorus neopenityl cyclopentadienyl is cyclopentadienyl, Y is cyclopentadienyl. phosphorus neopenty phenyl 28. The compound of claim 1, where N is arsenic, X phosphorus cyclopentadienyl cyclopentadienyl is cyclopentadienyl, Y is phenyl. 25 29. The compound of claim 1, where N is phospho 2. The compound of claim 1, where N is arsenic, X is rus, X is methyl, Y is selected from s-butyl, i-butyl, and hydride, Y is selected from s-butyl and i-butyl. t-butyl. 3. The compound of claim 1, where N is arsenic, X is 30. The compound of claim 1, where N is phospho hydride, Y is pentyl. rus, X is methyl, Y is pentyl. 4. The compound of claim 1, where N is arsenic, X is 30 31. The compound of claim 1, where N is phospho hydride, Y is cyclopentadienyl. rus, X is methyl, Y is cyclopentadienyl. 32. The compound of claim 1, where N is phospho 5. The compound of claim 1, where N is arsenic, X is rus, X is ethyl, Y is propyl. methyl, Y is isopropyl. 33. The compound of claim 1, where N is phospho 6. The compound of claim 1, where N is arsenic, X is 35 rus, X is ethyl, Y is butyl. methyl, Y is butyl. 34. The compound of claim 1, where N is phospho 7. The compound of claim 1, where N is arsenic, X is rus, X is ethyl, Y is pentyl. methyl, Y is pentyl. 35. The compound of claim 1, where N is phospho 8. The compound of claim 1, where N is arsenic, X is rus, X is ethyl, Y is cyclopentadienyl. methyl, Y is cyclopentadienyl. 40 36. The compound of claim 1, where N is phospho 9. The compound of claim 1, where N is arsenic, X is rus, X is propyl, Y is pentyl. ethyl, Y is propyl. 37. The compound of claim 1, where N is phospho 10. The compound of claim 1, where N is arsenic, X rus, X is propyl, Y is cyclopentadienyl. is ethyl, Y is butyl. 38. The compound of claim 1, where N is phospho 11. The compound of claim 1, where N is arsenic, X 45 rus, X is propyl, Y is phenyl. is ethyl, Y is pentyl. 39. The compound of claim 1, where N is phospho 12. The compound of claim 1, where N is arsenic, X rus, X is butyl, Y is pentyl. is ethyl, Y is cyclopentadienyl. 40. The compound of claim 1, where N is phospho 13. The compound of claim 1, where N is arsenic, X rus, X is butyl, Y is cyclopentadienyl. is ethyl, Y is phenyl. 50 41. The compound of claim 1, where N is phospho 14. The compound of claim 1, where N is arsenic, X rus, X is pentyl, Y is cyclopentadienyl. is n-propyl, Y is isopropyl. 42. The compound of claim 1, where N is phospho 15. The compound of claim 1, where N is arsenic, X rus, X is pentyl, Y is phenyl. is propyl, Y is butyl. 43. The compound of claim 1, where N is phosporus, 16. The compound of claim 1, where N is arsenic, X 55 X is cyclopentadienyl, Y is cyclopentadienyl. is propyl, Y is pentyl. : s