LOW-TEMPERATURE GAAS METALORGANIC CHEMICAL VAPOR-DEPOSITION USING DIMETHYLAMINE GALLANE AND ARSINE

Dimethylamine gallane (DMAG) is used for low-temperature GaAs metalorganic chemical vapor deposition (MOCVD) because it has a much lower decomposition onset temperature than trialkyl Ga sources. We grow GaAs layers using the simultaneous supply mode (conventional MOCVD) and an alternate supply mode (flow-rate modulation epitaxy-FME) for DMAG and arsine, and compare their electrical and optical properties. Mirror-like surfaces are obtained at substrate temperatures above 250-degrees-C, and low-temperature photoluminescence spectra show different excitonic features for both supply modes. For the simultaneous supply mode, an increase in arsine partial pressure during growth shifts the bound exciton peak to a longer wavelength due to the increase of the defect-related exciton peak. For the FME mode however, no peak shift is observed with increasing arsine partial pressure, indicating that defect incorporation is well suppressed in FME.