Surface ordering of MBE grown 001 gallium(05) aluminum(05) arsenic: A theoretical study
The surface kinetics of MBE growth of 001 {dollar}Ga\sb{x}Al\sb{1-x}As{dollar} is studied theoretically using the stochastic model which is based on the master equation approach and random distribution approximation. The kinetic processes included in the model are adsorption and surface migration. The surface ordering kinetics is studied as function of fluxes, flux ratio and substrate temperature. The growth parameters employed for the monatomic spices As are: fluxes 2{dollar}\sp\circ{dollar} A/sec, for cations with the cation to anion flux ratios 1: 10, and 1: 20. The growth parameter employ for the diatomic spices {dollar}As\sb2{dollar} are: fluxes 2{dollar}\sp\circ{dollar} A/sec. for cations with the cation to anion flux ratios 1: 10, 1: 20, and 1: 30, for cations to anions. The degree of ordering was obtained in terms of short range order (SRO), parameter. The surface ordering kinetics observed can be described in terms of effective surface migration rates of cations as follows. Lower temperature higher flux ratio results in smaller effective surface migration rates for cation. Beyond transition temperature the thermal energy, {dollar}\kappa\sb{B}T{dollar}, is large enough to break the Al-Ga bonds and causes thermal randomization of the Ga-Ga, Al-Al, and Ga-Al bonds. (Abstract shortened by UMI.).
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