Crystal orientation dependence of silicon autocompensation in molecular beam epitaxial gallium arsenide

Abstract

Silicon-doped GaAs has been grown simultaneously on (100), (110), and (111)B oriented GaAs substrates by molecular beam epitaxy. For constant Si, Ga, and As4 fluxes the surface morphology of the (110) and (111)B faces degraded with increasing substrate temperature above ∼500 °C. (100) films had an n-type free-electron concentration of 5×1016 cm−3 independent of substrate temperature. Films on (110) substrates were p type when grown above ∼550 °C and n type below ∼550 °C whereas (111)B films were highly resisitive under most growth conditions. Low-temperature (4 K) photoluminescence showed good correlation between the Si acceptor peak heights and the compensation ratios derived from electrical measurements.