| Atomic layer epitaxy (ALE) is a useful thin film growth technique that allows precise control of film thicknesses over large substrate areas. In ALE the growth of thin films proceeds one layer of atoms at a time, by the alternate exposure of a substrate to reactant gases. In the self-limited, or ALE processing regime the growth rate is insensitive to processing temperature, reactant concentrations, and processing times. Under these conditions the film growth is only a function of the number of reactant exposures or cycles.; Application of ALE as a viable film growth process has been limited by the need for specific reactants. For instance, self-limited growth of a binary compound requires two reactants with overlapping temperature-insensitive processing windows. This restriction has made it difficult or impossible to achieve self-limited growth in some material systems.; A combination of limited reaction processing (LRP) and atomic layer epitaxy (ALELRP) allows thermal tailoring of the ALE process. LRP is a thin film growth technique in which the temperature of the substrate may be rapidly changed during growth. For the ALELRP process, the restriction of overlapping temperature processing windows is relaxed since each reactant can be processed at its optimum temperature.; In this thesis the ALELRP technique is applied to the growth of cadmium telluride thin films using dimethyl cadmium (DMCd) and diisopropyl telluride (DIPTe). Experimental work includes the determination of the ALE processing regime for the reactants, and a comparison of ALELRP and OMVPE-grown films. Results show that the temperature processing windows for DMCd and DIPTe differ by about 125{dollar}spcirc{dollar}C. Consequently, isothermal ALE of CdTe using these reactants is probably not possible. Comparison of ALELRP and OMVPE-grown films show that ALELRP films have superior crystal quality, uniformity, and surface morphology.; The thesis also presents a computer model, based on the principles of chemical kinetics, to explain the observed self-limited growth of cadmium telluride using ALELRP. Using a mechanism based on surface and gas phase reactions, a good fit to nearly all experimental data was obtained with physically reasonable values for rate parameters. |
