Quantitative depth profile analysis of InP/InGaAs hetero-interfaces by as carry-over

Abstract Although it is important to investigate the hetero-interface of III-V semiconductor devices for highly efficient solar cell or photo-detector, it is not trivial to measure structural property at interface due to problems related to thickness and small compositional variation of interface layer to clearly observe current measurement systems. In this study, to investigate the interfaces of InP/InGaAs structures grown on InP substrates, two different samples were prepared. One was grown at lattice parameter of InP and InGaAs matched condition. The other has arsenic contained interface between InP/InGaAs leaving growth interruption process out. It was found that the InP capping layer without growth interruption included about 1% of arsenic due to arsenic carry-over. For depth profiling analysis using HRXRD, we developed the combinational method of InP selective etching technique and HRXRD. As a result, we could successfully demonstrate that the compositionally graded interface that generated from arsenic carry-over could be quantified. We also reveals approximately 170 nm thickness of interface layer which is thicker than generally reported values originated from residual arsenic in deposition chamber.