The Atmospheric Chemical Vapour Deposition Of Coatings On Glass. by Kevin David Sanderson, B.Sc. A thesis submitted to Imperial College of Science Technology and Medicine for the degree of Doctor of Philosophy January, 1996 The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the author. Some of the material presented in this thesis is of a confidential nature. It is therefore requested that anyone reading this thesis maintains this confidentiality until the thesis becomes publicly available. Abstract: The deposition of thin films of indium oxide, tin doped indium oxide (ITO) and titanium nitride for solar control applications have been investigated by Atmospheric Chemical Vapour Deposition (APCVD). Experimental details of the deposition system and the techniques used to characterise the films are presented. Results from investigations into the deposition parameters, the film microstructure and film material properties are discussed. A range of precursors were investigated for the deposition of indium oxide. The effect of pre-mixing the vaporised precursor with an oxidant source and the deposition temperature has been studied. Polycrystalline In203 films with a resistivity of 1.1 - 3 x 10-3 ) cm were obtained with In(thd)3 , oxygen and nitrogen. The growth of ITO films from In(thd)3, oxygen and a range of tin dopants is also presented. The effect of the dopant precursor, the doping concentration, deposition temperature and the effect of additives on film growth and microstructure is discussed. Control over the preferred orientation growth of ITO has been achieved by the addition of acetate species during film growth. Insitu infra-red spectroscopy has been used to identify the gas phase species and identify the species responsible for the film modification. ITO films with a resistivities of 1.5 - 4 x 104 n cm have been achieved. The deposition of titanium nitride by the APCVD of Ti(NMe2)4 and a mixture of Ti(NMe2)4 and ammonia is reported. Contamination of the films and pre-reaction between the precursors in the gas phase is discussed, and the synthesis of new precursors for the deposition of titanium nitride is reported. New precursors have been synthesised under anaerobic conditions and characterised by infra-red spectroscopy, 'H and it NMR, mass spectrometry, thermal gravemetric analysis and three by single crystal X-ray diffraction. Deposition of titanium nitride utilising two new precursors is reported. Acknowledgments I would like to express my thanks to my supervisors Professor Mingos at Imperial College and Dr. David Sheel at Pilkington Technology Centre for giving me the opportunity to carry out this work and for their support throughout my studies. To my parents, grandparents and sister Kerry for all their support throughout not only this work but all that went before, and without whom I would not have had the strength or resolve to come this far. A special thanks goes to my grandparents who despite no longer being alive, I still feel indebted to for their love and support; which they gave so freely and which at many times gave me the confidence to go further. I would also like to thank the members of the group at Imperial College, D. Otway, J. Darr, J. Plakatouros, J. McAleese, C. Arunaslam and S. Miller for their help through some trying times at Imperial and the Tight Line Tour 94 will be something that I shall never forget. To all the other people who I have had the good fortune to be associated with over the last three years but unfortunately number too many to be listed individually, I would like to pass on my thanks for their help, advice and support. But a mention has to go to Fisherman Boden and HF Culshaw, for all the good humored (or was it ? I'm not quite sure !) abuse that they gave me. A special thanks must also go to Dr. Helen Sanders for her valuable assistance with the Infra-Red Work. Finally I would like to thank Christine who has been supportive, and patient beyond belief, whilst I have been writing this thesis, helping me to remain sane throughout. Abbreviations Used: acac 2,4-pentanedione AFM Atomic Force Microscopy APCVD Atmospheric Pressure Chemical Vapour Deposition BuOAc Butylacetate CVD Chemical Vapour Deposition DBTDA Diacetatodibutyltin DMT Dichlorodimethyltin DMTDA Diacetatodimethyltin FTIR Fourier Transform Infra Red Spectroscopy ITO Tin Doped Indium Oxide NMR Nuclear Magnetic Resonance Spectroscopy PVD Physical Vapour Deposition SEM Scanning Electron Microscopy SV Set Point TCO Transparent Conducting Oxide TGA Thermal Gravimetric Analysis thd 2,2,6,6-tetramethylheptanedione THE Tetrahydrofuran XRD X-ray Diffraction XRF X-ray Fluorescence 1. Introduction. 1 1.1 Background. 1 1.2 Chemical Vapour Deposition. 4 1.3 Chemical Vapour Deposition In The Glass Industry. 14 1.3.1 Anti Reflection Coatings. 14 1.3.2 Liquid Crystal / Electrochromics. 14 1.3.3 Solar Control Films. 16 1.3.4 Low Emissivity Coatings. 16 1.4 Scope Of This Study. 19 1.5 References. 20 2. Apparatus Design and Description. 23 2.1 Introduction. 23 2.2 Gas Handling System. 23 2.3 CVD Reactor. 27 2.4 Temperature Profile Of Reactor. 30 2.5 Reactor Hydrodynamics. 34 2.6 Substrates. 37 2.7 Film Analysis. 40 2.7.1 Electrical and Thickness Characterisation. 40 2.7.2 Hall Effect Measurements. 41 2.7.3 X-Ray Diffraction (XRD). 44 2.7.4 Auger Analysis. 45 2.7.5 X-Ray Fluorescence. 45 2.7.6 Optical Measurements. 46 2.7.6.1 Haze Test. 46 2.7.6.2 Infrared Reflectance and Visible Reflectance Spectra. 46 2.8 Chemicals Used For In203 / ITO Work. 47 2.9 Chemicals Used For the Titanium Nitride Work. 48 2.10 Chemical Analysis Techniques. 48 2.10.1 Mass Spectrum. 48 2.10.2 'H and 13C NMR Spectroscopy. 48 i 2.10.3 Microanalyses. 48 2.10.4 TGA/DSC. 49 2.10.5 Single Crystal X-ray Structure Determination. 49 2.10.6 Infra-Red Spectroscopy. 49 2.11 References. 49 3. Growth Of In203 By Atmospheric Pressure Chemical Vapour Deposition. 51 3.1 Background. 51 3.2 Transparent Conducting Oxides TCO's. 52 3.3 Indium Oxide and ITO Deposition. 55 3.4 Experimental. 59 3.5 Results and Discussion. 60 3.5.1 The Growth of In203 From Trimethylindium-adducts. 60 3.5.1.1 Background. 60 3.5.1.2 Growth From Me3In(OEt2). 62 3.5.1.3 Growth of In203 From Me3In(THF). 63 3.5.1.3.1 Effect of Substrate Temperature On In203 Growth. 67 3.5.1.3.2 Effect Of Oxygen Concentration On In203 Growth. 68 3.5.1.3.3 Effect Of Precursor Stability On In203 Growth. 69 3.5.1.3.4 Summary of Me3In Adduct Precursors. 70 3.5.2 Growth Of In203 From Indium Tris-P-diketonates. 71 3.5.2.1 Background. 71 3.5.2.2 Growth of In203 From In(acac)3. 72 3.5.2.2.1 Effect Of Deposition Temperature On Film Growth. 75 3.5.2.3 Growth of In2O3 From In(thd)3. 76 3.5.2.3.1 Effect of Temperature on Film Growth. 79 3.5.2.3.2 Effect of Oxygen Concentration. 79 3.5.2.3.3 Nature of Film Growth. 80 3.5.2.4 Summary of In203 Growth From Indium-J3-diketonates. 84 3.5.3 Growth Of In203 From Dimethylindium compounds. 85 3.5.3.1 Growth of In203 From Me2In(OMe). 85 3.6 Conclusions. 87 3.7 References. 88 ii 4. Growth Of ITO From In(thd)A and a Range of Tin Dopants. 91 4.1 Aim. 91 4.2 Experimental. 91 4.3 Results and Discussion. 91 4.3.1 Effect of Solvent on the growth of In203. 91 4.3.2 ITO Growth From In(thd)3 and DMT. 94 4.3.2.1 Effect of Dopant Concentration on Film Properties. 94 4.3.2.1.1 Effect of Dopant Concentration on Films Electrical Properties 94 4.3.2.1.2 Effect of Dopant Concentration on Film Crystallinity. 104 4.3.2.2 Effect of Growth Temperature. 111 4.3.2.3 Effect of Solvent Addition. 112 4.3.2.3.1 Effect of Solvent Addition at 565°C. 113 4.3.2.3.2 Effect of Solvent Addition at 625°C. 122 4.3.3 ITO Film Growth From In(thd)3 and DMTDA. 123 4.3.3.1 Effect of Dopant Concentration on Film Properties. 123 4.3.3.2 Effect of deposition temperature on film growth. 125 4.3.3.3 Effect of butylacetate addition on film growth. 130 4.3.4 ITO Film Growth From In(thd)3 and Sn(II) Salt of Ethyl-hexanoic Acid. 133 4.3.4.1 Effect of Tin Dopant Concentration. 133 4.3.4.2 Effect of Solvent On Dopant Solution and Film Properties. 134 4.3.4.3 Effect of Temperature. 136 4.3.4.4 Effect of Oxygen Concentration. 139 4.3.4.5 Effect of Film Thickness. 139 4.3.5 Doping With Diacetatodibutyltin (DBTDA). 141 4.3.5.1 Effect of Dopant Concentration on Film Properties. 141 4.3.5.2 Effect of Temperature on Film Growth. 145 4.3.6 Tin Tetrachloride Doping Of In(thd)3 145 4.3.6.1 Effect of Dopant Concentration on Film properties. 145 4.3.6.2 Temperature Effect. 148 4.4 Conclusions. 152 4.5 References. 153 iii 5. Investigation of the Role of Solvents in The Deposition of ITO By Gas Phase IR Spectroscopy.