Quantification of trap densities at dielectric/III–V semiconductor interfaces

High-frequency capacitance-voltage curves for capacitors with high-k gate dielectrics and III–V semiconductor channels are modeled. The model takes into account the low conduction band density of states, the nonparabolicity of the Γ valley, and the population of higher lying conduction band valleys. The model is used to determine interface trap densities (Dit) and band bending of HfO2/In0.53Ga0.47As interfaces with different Dit and with pinned and unpinned Fermi levels, respectively. Potential sources of errors in extracting Dit are discussed and criteria that establish unpinned interfaces are developed.