Study of Sb segregation and As diffusion in InP/GaAsSb/InP heterostructures using soft and hard x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry

Abstract

We investigate the chemical composition of InP/GaAs0.51Sb0.49/InP heterostructures, focusing on a precise location of the major elements to search for potential Sb segregation and As diffusion. Angle-resolved x-ray photoelectron spectroscopy demonstrates approximately 1.2 ± 0.1 at. % antimony segregation in the top InP layer, along with the absence of arsenic diffusion. Hard x-ray photoelectron spectroscopy (HAXPES) is also implemented to get complementary information about the top InP/GaAs0.51Sb0.49 interface. The theoretical modeling of HAXPES intensity ratios is compared with data collected at various angles, highlighting Sb segregation and no As diffusion through the top InP layer. Time-of-flight secondary ion mass spectrometry data confirm the effective presence of Sb all along this InP layer and negligible As diffusion. It shows also that this Sb segregation during growth does not affect the composition of the GaAsSb critical layer.