In situ characterisation of MOVPE by surface photoabsorption: I. Substrate oxide desorption

Abstract

We report on the use of surface photoabsorption (SPA) as an in situ technique for monitoring III–V semiconductors in an MOVPE reactor. The technique gives information about the oxide desorption of various III–V substrates before growth. We find that the oxides from acid-etched GaAs desorb slowly even at high temperature (>650°C) unless atomic hydrogen is present. Alkali-etched GaAs oxides are desorbed at a much lower temperature (<440°C). The shape and temperature range (260–410°C) of the optical response associated with InAs and GaAs deoxidation is quite different to that from InSb and GaSb (260–530°C).