Control of beryllium redistribution in InP grown by gas source molecular beam epitaxy

Beryllium is widely used in molecular beam epitaxy (MBE) as a p-type dopant. The authors report on the diffusion of Be in InP with beryllium concentrations in excess of 1×10¹⁹ cm^-3 during growth by gas-source MBE. Diffusion profiles are analyzed by secondary ion mass spectrometry and C(V) profiling. The dependency of diffusion on the type and doping of InP is investigated. It was found experimentally that diffusion depths are mainly correlated to the heavily-doped layer thickness, and strongly depend on the type and doping level of the host material. This is consistent with a mechanism of fast diffusing positively charged interstitial, further incorporated as a substitutional, with an electrical activity close to 1, as shown by C(V) profiling. Diffusion of Be in InP:Fe shows a peculiar iron out-diffusion induced by the excess interstitial Be