INTERFACE FORMATION OF DEPOSITED INSULATOR LAYERS ON GAAS AND INP

The factors which influence the interface formation of deposited layers are discussed. This paper models the insulator/semiconductor interface formation during chemical vapor deposition (CVD) of SiO2 and SiON onto InP and GaAs; it deals primarily with the chemical nature of the interface as a result of the CVD and not with the electronic properties of the interface. Although specific examples of SiO2 and SiON films chemically vapor deposited onto InP and GaAs are given, the modeling should be useful for all the III-V compounds. Thermal decomposition of the surface, substrate thermal oxidation, surface reactions and interdiffusion of the substrate and deposited layers are considered. The previously published experimental data on the diffusion and reaction of gallium, arsenic, indium and phosphorus with thermally grown SiO2 on silicon serve as the framework for the deposited layer interface model presented in this work. Auger analysis and electron spectroscopy for chemical analysis are used to demonstrate the applicability of the model and to provide information on the chemistry of the deposited layer/GaAs and deposited layer/InP interfaces. It is found that the SiO2/InP interface is similar to that predicted by the model whilst the SiON/GaAs interface is not. The SiO2/InP interface contains an In2O3P2O5 layer when the deposition occurs at 450 °C but not when the deposition occurs at 340 °C. Indium diffusion occurs at both temperatures. No Ga2O3 or As2O3 was detected at the SiON/GaAs interface, but a high concentration SiO2 layer was observed which appears to be the result of gettering of oxygen gas from the reactor chamber. © 1979.