A NEW REACTOR SYSTEM FOR MOCVD OF ZNSE - MODELING AND EXPERIMENTAL RESULTS FOR GROWTH FROM DIMETHYLZINC AND DIETHYLSELENIDE

The performance of a new vertical reactor for metalorganic chemical vapor deposition (MOCVD) of ZaSe has been characterized and optimized through combined numerical modelling and experimental investigations. Finite element computations of the flow field in the reactor are used to identify transport mechanisms of impurities and to optimize the reactor inlet to susceptor distance. The quality of the as-grown ZnSe in terms of photoluminescence characteristics is shown to deteriorate with increasing strength of flow recirculation cells in the reactor. The ZnSe films have been grown on (100)GaAs substrates by using diethylselenide and dimethylzinc. The dependence of the growth rate on substrate temperature, reactor configuration is reported. For temperatures above 500°C the growth is mass transfer limited. Photoluminescence spectra of films grown at optimal conditions show dominant free excitonic emission with weak donor and acceptor bound excitonic transitions. Weak and broad deep-level transitions are also detected. Carbon incorporation is observed to occur at high values of the [VI/II] ratio. Although the films are highly resistive, the photoluminescence spectra indicate that the overall quality of the as-grown ZnSe films is very good. © 1990.