Effect of group V partial pressure on the kinetics of selective area MOVPE for GaAs on (1 0 0) exact and misoriented substrate

Abstract

Surface reaction kinetics of GaAs growth by metalorganic vapor phase epitaxy (MOVPE) was investigated by examining the growth rate non-uniformity of open area in selective area MOVPE. The surface reaction rate constant ( k s) could be extracted using this technique and the effect of tertiarybutylarsine (TBAs) partial pressure ( p TBAs) on k s was examined on GaAs (1 0 0) exact and misoriented substrates in the temperature range 550–700 °C. The activation energy of k s was significantly dependent on the growth temperature range and on p TBAs. This is due to the change of the probable reactant formed by the gas-phase reaction and also due to the GaAs (1 0 0) surface reconstruction which depends on temperature and p TBAs. At 575 and 700 °C, the relation between k s and p TBAs was examined at a constant trimethylgallium (TMGa) partial pressure or V/III ratio, respectively. The desorption of As from the GaAs surface should be taken into account at lower p TBAs. At higher p TBAs, the surface reconstruction state, the potential reaction between As species and As sites on the surface and the organic by-product from TBAs might be responsible for the reduction of k s value.