XPS study of GaInP on GaAs interface

We have studied the interface between lattice-matched GaInP and GaAs grown by gas source molecular beam epitaxy at 400 and 500°C using angle resolved X-ray photoelectron spectroscopy. We show that the In segregation in GaInP is less effective than in the case of GaInAs on GaAs with a segregation energy around 0.1 eV at 500°C. As regards the anions, the As segregation alone can not account for the rather large As amount detected in the GaInP layer. This is mainly related to some AsH3 injection together with PH3 at the beginning of GaInP growth. Nevertheless, although large chemical bond strength differences between anions and cations exist at the interface which could lead to important interdiffusion processes, the reaction between GaAs and GaInP is impeded up to 500°C. This in turn implies that with an optimized gas commutation sequence, it should be possible to grow nearly abrupt interfaces between GaAs and GaInP at 500°C.