Impact of Quantum Capacitance on Intrinsic Inversion Capacitance Characteristics and Inversion-Charge Loss for Multigate III-V-on-Insulator nMOSFETs

Abstract

This paper investigates the impact of quantum capacitance on the intrinsic inversion-capacitance (C-inv) characteristics of high-mobility multigate III-V-on-insulator nMOSFETs through a numerical simulation corroborated by the theoretical calculation. Nonmonotonic C-inv characteristics stemming from the energy dependence of 1-D density-of-states and significant C-inv degradation due to quantum capacitance have been found in trigate In0.53Ga0.47As and InAs devices based on the ITRS 2018-2024 technology nodes. This paper indicates that, to compensate the excess inversion-charge (Q(inv)) loss due to quantum capacitance, the needed mobility gain of the trigate InGaAs and InAs devices (against the Si counterparts) should be at least similar to 3x and similar to 4x, respectively. This paper also suggests that the quantum-capacitance-induced Q(inv) loss can be mitigated by raising the fin aspect ratio of the III-V multigate device.