XPS STUDY OF GAINP ON GAAS INTERFACE

We have studied the interface between lattice-matched GaInP and GaAs g rown by gas source molecular beam epitaxy at 400 and 500 degrees C usi ng angle resolved X-ray photoelectron spectroscopy. We show that the I n segregation in GaInP is less effective than in the case of GaInAs on GaAs with a segregation energy around 0.1 eV at 500 degrees C. As reg ards the anions, the As segregation alone can not account for the rath er large As amount detected in the GaInP layer. This is mainly related to some AsH3 injection together with PH3 at the beginning of GaInP gr owth. 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 GaIn P is impeded up to 500 degrees C. This in turn implies that with an op timized gas commutation sequence, it should be possible to grow nearly abrupt interfaces between GaAs and GaInP at 500 degrees C. (C) 1998 E lsevier Science B.V.