Spectroscopic studies of the influence of oxygen partial pressure on the incorporation of residual silicon impurities in vapor-phase epitaxial gallium arsenide

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Abstract
The incorporation of residual shallow impurity species, in particular Si, in both chloride and hydride vapor-phase epitaxial GaAs layers grown with oxygen intentionally injected into the source zone has been studied. Photothermal ionization spectroscopy and photoluminescence show that both the Si donor and acceptor concentrations are significantly reduced by the oxygen. The observed reduction of carrier concentration and the increase in Hall mobility with increasing oxygen partial pressure are mainly due to the reduction of Si impurity concentration. Although oxygen can form deep levels as indicated by the 1.4889-eV bound-exciton line in photoluminescence, the main effect of oxygen injection is to improve the material purity by suppression of the incorporation of residual Si.