Evaluation of interface traps inside the conduction band of InAs-on-insulator nMOSFET by self-consistent Hall-QSCV method

Abstract

Interface trap density (Dit) inside the conduction band of (111)-oriented InAs-on-insulator (InAs-OI) n-channel metal-oxide-semiconductor field-effect-transistor (nMOSFET) was experimentally evaluated by developing a method through a combination of a Hall measurement and quasi-static split C–V (Hall-QSCV). The surface potential and Dit of the InAs-OI nMOSFET were self-consistently calculated by numerically solving the Schrödinger–Poisson equation. The energy distributions of Dit were found to be almost independent of the ultra-thin-body channel thickness and the quantization energy, indicating the validity of the proposed Hall-QSCV evaluation. The energy position of the Dit minimum is in good agreement with the theoretically predicted position of the charge neutrality level, which locates deeply inside the conduction band of InAs. The experimental maximum surface electron density Nsmax at the InAs MOS interface, limited by Fermi level pinning, is 1.2 × 1013 cm−2, which is 2–3 times higher than Nsmax at the In0.53Ga0.47As MOS interfaces, owing to the lower Dit inside the InAs conduction band.