KINETIC MODELING OF GAAS CHEMICAL BEAM EPITAXY

We report results of kinetic modelling of the growth of GaAs by chemic al beam epitaxy (CBE) with an effusive beam of triethylgallium (TEGa). The model is an extension of one reported previously and includes new reactions and Arrhenius parameters reported in recent UHV surface stu dies. The model provides excellent fits to growth rates measured as a function of substrate temperature and TEGa beam flux. The major conclu sions are: (1) at low temperature the increase in growth rate with tem perature is due to an increase in the rate limiting desorption of hydr ocarbon products (C2H4 and C2H5), and (2) at high temperature, the fal l-off in growth rate is a consequence of precursor-mediated adsorption of TEGa, i.e. as temperature increases, desorption of TEGa begins to compete with dissociation.