Analytical models for growth by metal organic vapour phase epitaxy: II. Influence of temperature gradient

Abstract

For pt.I see ibid., vol.5, p.16 (1990). Analytical descriptions are given of the growth rate in metal organic vapour phase epitaxy processes in the medium- and higher-temperature regions, where growth is controlled by diffusional transport through the gas phase and desorption of growth species, respectively. In continuation of part I, where only isothermal problems were considered, the temperature-dependent hydrodynamic behaviour is now investigated. A temperature gradient is introduced and the effect of thermal diffusion on the growth rate is studied, which is significant: a much ( approximately 40%) lower depletion is calculated if thermal diffusion is included. Furthermore the influence of surface reactions at high and low temperatures is investigated, resulting in a model in which the CVD number plays an important role. This model allows for the calculation of growth rates in both the diffusion-limited as well as the high-temperature region, where desorption dominates.