Materials Science and Engineering, 31 (2001) 1±438 Guide to references on III±V semiconductor chemical etching A.R. Clawson* Department of Electrical and Computer Engineering, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0407, USA Accepted 27 August 2000 Abstract The literature on chemical etching of III±V semiconductors is reviewed with the intent to organize citations in categories useful to device and materials investigators. Descriptive citations are grouped by the intended etch application and subgrouped by specific semiconductors for both wet and dry etching. A separate section groups citations by the various chemical compositions used as etchants so that a broad view of results and issues can be accessed. The final section lists references by author, with complete titles and notes of their relevance to etching. # 2001 Elsevier Science B.V. All rights reserved. Keywords: Chemical etching; Wet etchants; Dry etchants 1. Introduction There is a large extent of literature on etchants, but it is frequently hard to locate specific information. The purpose of this reference guide is to direct the III±V semiconductor device researcher to chemical etchants suitable for particular applications and provide descriptions and useful results. There are many excellent reviews of etchants that provide background for un- derstanding the chemistry, and which give limited lists of applicable etchants with references. There are also many investigations characterizing specific etchants in detail. Other etchants are simply described as a side issue to their application in device fabrication or materials characterization. The references compiled here give a very broad sampling of what is available up to April 2000. This guide is given as four annotated sections to make the etching information as accessible as possible. Section 2 lists wet etchants by there applications, Section 3 lists dry etchants by their application, Section 4 lists the wet chemical etchants by chemical composition, and the last part is a list of the references, providing both titles and notation of the contents to establish the context of the etchant data. The wet etchant application categories in Section 2 are grouped into common themes. Notes on different etchants are given, however, no judgement is made about the significance of the data. Some information is valuable and some is trivial, yet may give insight into device fabrication. Citations to references in the last part are indicated by first author's name and year with postscripts a, b, c, etc. when multiple references occur for a particular year. * Tel.: 1-858-534-7919. E-mail address: [email protected] (A.R. Clawson). 0927-796X/01/$ ± see front matter # 2001 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 7 - 7 9 6 X ( 0 0 ) 0 0 0 2 7 - 9 2 A.R. Clawson / Materials Science and Engineering 31 (2001) 1±438 The dry etchant application categories in Section 3 are grouped into common themes. As with Section 2, citations to references in the last part are indicated by first author's name and year with postscripts a, b, c, etc. when multiple references occur for a particular year. The wet chemical etchant list in Section 4 is ordered alphabetically by chemical, however, reference notes are grouped under only one arbitrarily chosen component of multi-component etchants. Other commutations of the components are included to direct the reader to the appropriate listing. H2O is usually not considered as a designated chemical component in the list, thus in most cases dilute and concentrated etchants are grouped together. The etchant reference list of the last part is ordered alphabetically by first author. Complete titles and notes are given. The notes include data on materials, etch rates and specific etch conditions when possible. Hopefully this guide will help lead to the appropriate literature for detailed information. 2. Wet etch applications 2.1. Wet chemical etching reviews Review of wet chemical etching of III±Vs, covering electrochemical mechanisms of etching and practical application of etchants; material selective etchants, defect revealing etchants, profile etching; Ref. (Notten, P.H.L., 1993) III±V semiconductor etchant review: gives pre-1962 data on chemical etchants for InSb, GaSb, AlSb, InAs, GaAs, InP, GaP; Ref. (Faust, J.W., 1962) Review: general discussion of etch pit dislocation and hillock formation; Ref. (Faust, J.W., 1959) Review of electrochemical behavior of semiconductor electrodes; Ref. (Gerischer, H., 1959) Treatise on photochemical behavior of semiconductors; discusses thermodynamics and kinetics of photodecomposition and function of electrolyte junction solar cells; Ref. (Gerischer, H., 1979) Review: silicon defect etch pit delineation; Ref. (Heimann, R.B., 1982) Review of III±V etching; describes mechanisms for (1) anodic (electrochemical) etching; (2) electroless etching (redox potential driven and illumination driven); (3) chemical etching; Ref. (Kelly, J.J., 1988) Review of Si and Ge etching; GaAs etching, GaAs electrochemical etching, GaAs thermochemical etching; GaP etching; Ref. (Kern, W., 1978a) Review: chemical etching of insulators, semiconductors, and conductors; describes etching principles and techniques; provides tables of etchants for GaAs, GaP, AlN, BN, BP, AlSb, GaN, GaSb, InAs, InP, InSb; Ref. (Kern, W., 1978b) Photochemical etching review: p±n dopant selectivity; surface relief etching; InGaAsP/InP and GaAs; Ref. (Kohl, P.A., 1989) A.R. Clawson / Materials Science and Engineering 31 (2001) 1±438 3 Treatise on photoelectrochemistry of semiconductor surfaces; Ref. (Pleskov, Yu.V., 1986) Review of GaAs etchant types, defect types, and defect revealing etchants; Ref. (Stirland, D.J., 1976) Review of etching behavior; gives definitions: Preferential Ð anisotropic etchants show markedly different etch rates on different low index crystallographic planes Non-preferential Ð etchants show etch rate independent of orientation Selective Ð etchants show markedly different etch rates for different semiconductor compositions Non-selective Ð etchants show etch rates independent of composition; Ref. (Tijburg, R., 1976a) Review of semiconductor etching; discusses chemical process, effect of illumination, effect of adding metal ions, and crystallographic effects. Gives tables of etchants for Si, Ge, SiC, GaAs, GaP, GaSb, InAs, InP, InSb, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, PbS; Ref. (Tuck, B., 1975) Review: InP etching overview; wet chemical and dry etching; Ref. (Adachi, S., 1990a) Review: GaAs etching overview; wet and dry etching; Ref. (Ashby, C.I.H., 1990a) Review: InP wet chemical etching; with (1) defect or damage revealing etchant table, (2) polishing etchant table, and (3) pattern etchant table; Ref. (Adachi, S., 1990b) Review: wet and dry chemical etching of GaAs; classifies wet etchants as non-electrolyte (those with rates which are diffusion limited or chemical reaction limited) and electrolyte (those based on anodic oxidation followed by dissolution of products); gives tables of wet and dry etchants; Ref. (Ashby, C.I.H., 1990f) Review of GaAs etching and surface preparation; discusses etching mechanisms, diffusion and reaction rate limiting etching, anodic etching, and surface preparation; Ref. (Mukherjee, S.D., 1985) Review: photochemical processing of semiconductors; Ref. (Rauth, D.R., 1992) Review: chemical etching principles: dissolution of ionic crystals; dissolution of semiconductors; etch pit formation; electrochemical etching; photoetching; gas phase etching; Ref. (Sangwal, K., 1992) Review: STM study of surface reconstruction and effect on etching behavior; Ref. (Boland, J.J., 1998) Review: electrochemistry of III±V semiconductors; Ref. (Gomes, W.P., 1994) Review: wet etching of GaAs H2SO4:H2O2:H2O; review of GaAs etch characteristics Br2/methanol; review of GaAs etch characteristics Electrochemical etching of GaAs; review of anodic and cathodic etch characteristics; Ref. (Williams, R., 1990b) 4 A.R. Clawson / Materials Science and Engineering 31 (2001) 1±438 2.2. Wet chemical lattice feature delineation Etch pit defect delineation etchants InP HBr:CH3COOH (1:10); InP defect delineation; etch rate 1:7 mm/min; Ref. (Akita, K., 1979) HBr:HF (10:1); InP defect delineation; etch rate 0:9 mm/min; Ref. (Akita, K., 1979) HBr:HF (1:5) and (1:10); InP dislocation etch pit delineation study with A±B etch comparison; Ref. (Kotani, T., 1980) HBr:HF (1:5); InP dislocation etch pit delineation for 5 min at 208C; Ref. (Susa, N., 1980a,c, 1981) HBr:H3PO4 (1:2) {Huber etch}; InP defect delineation; etch rate 0:25 mm/min; gives data on etch rates and etch pit delineation versus etchant composition; Ref. (Akita, K., 1979) HBr:H3PO4 (1:2) {Huber etch}; InP, delineation of pits, ridges, and striations, 1±2 min at 208C; Ref. (Brown, G.T., 1980) HBr:H3PO4 (1:2) {Huber etch}; InP dislocation etch pit delineation; Ref. (Huber, A., 1975) HBr:H3PO4 (1:2) {Huber etch}; InP dislocation etch pit delineation for 150 s; Ref. (Westphalen, R., 1989) HBr:H3PO4 (1:2) {Huber etch}; InP first step etch pit delineation; 1±2 min at 208Cgives symmetrical etch pits; followed by H2SO4:H2O2:H2O (1:1:1); InP second step free etch of 30 mm for elongated etch pit delineation for (1 0 0) orientation determination; 5 min at 858C; Ref. (Caridi, E.A., 1984) HBr:H3PO4 (1:2) {Huber etch}; Application: InP and InGaAsP epilayer etch pit defect delineation at room temperature; Ref. (Nakamura, M., 1993) H3PO4:HBr (2:1) {Huber etch}; Application: InP dislocation etch pit delineation; Ref. (Tamari, N., 1982a) H3PO4:HBr (2:1) (Huber etch); Application: InP defect delineation etch; 2 min at room temperature. CrO3:AgNO3:H2O:HF (1 g:8 mg:2 ml:1 ml) (A±B etch); Application: InP defect delineation etch; 60 min at 608C; Ref. (Hirano, R., 1993) HBr:H3PO4 (1:2) (Huber etch); Application: InP and InGaAsP defect delineation in 4 mm thick epilayers; Ref. (Nakamura, M., 1993) H3PO4:HBr (2:1) {Huber etch}; Application: InP dislocation etch pit delineation; Ref. (Kimura, T., 1991) HBr:HNO3 (3:1); InP dislocation delineation on (1 1 1) and (1 0 0); Ref.