Impact of quantum capacitance on intrinsic inversion capacitance characteristics and inversion-charge loss for multigate III-V-on-Insulator nMOSFETs

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 In_0.53Ga_0.47As 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 ∼3× and ∼4×, 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.