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

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 (ks) could be extracted using this technique and the effect of tertiarybutylarsine (TBAs) partial pressure (pTBAs) on ks was examined on GaAs (1 0 0) exact and misoriented substrates in the temperature range 550-700 °C. The activation energy of ks was significantly dependent on the growth temperature range and on pTBAs. 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 pTBAs. At 575 and 700 °C, the relation between ks and pTBAs 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 pTBAs. At higher pTBAs, 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 ks value.