Single Source Heterojunction Metal–Oxide–Semiconductor Transistors for Quasi-Ballistic Devices: Optimization of Source Heterostructures and Electron Velocity Characteristics at Low Temperature

Abstract

We have experimentally studied the electron velocity behavior of single source heterojunction metal–oxide–semiconductor field-effect transistor (SHOTs) without a drain energy spike fabricated by optimizing the source heterostructures. The electron velocity vE of SHOTs with source conduction band offset ΔEC strongly depends on the source heterojunction position, and the enhancement of vE for SHOTs relative to that for single drain-heterojunction transistors (DHOTs) and strained-Si-on-insulator devices (SSOIs) slightly increases with decreasing lattice temperature T. We have also found that vE for SHOTs, DHOTs, and SSOIs has a power law dependence on low-field electron mobility µEFF, that is, the mean free path of electrons λ at various T. Thus, the electron kinetic energy ΔEK converted by the source band offset in SHOTs increases with increasing mean free path of electrons at lower T. Using vE∝λα (α: constant), we can also estimate vE for both SHOTs and DHOTs at the ballistic transport limit.