In situ isotope study of indium diffusion in InP/Al2O3 stacks

A high-quality interface of III–V/high-k dielectrics is critical to obtain high-performance devices. Indium out-diffusion in an InP-based stack is correlated with the density of interface states. Diffused In species are in the form of oxides, which invite the question about the diffusion of species through the high-k dielectric layer. For an InP/Al2O3 stack, O18 isotope tracing is carried out to investigate if the interface oxygen and indium atoms diffuse together or not. This work sheds light on the fundamental mechanism for III–V semiconductors' interface elemental diffusion as well as the interface passivation strategy.