Analog and RF performance of doping-less tunnel FETs with $\hbox {Si}_{0.55} \hbox {Ge}_{0.45}$ source

Abstract

This paper reports studies of a doping-less tunnel field-effect transistor (TFET) with a $\hbox {Si}_{0.55} \hbox {Ge}_{0.45}$ source structure aimed at improving the performance of charge-plasma-based doping-less TFETs. The proposed device achieves an improved ON-state current ($I_{{\mathrm{ON}}} \sim {4.88} \times {10}^{-5}\,{\mathrm{A}}/\upmu {\mathrm{m}}$), an $I_\mathrm{ON}/I_\mathrm{OFF}$ ratio of ${6.91} \times {10}^{12}$, an average subthreshold slope ($\hbox {AV-SS}$) of $\sim$ ${64.79}\,{\mathrm{mV/dec}}$, and a point subthreshold slope (SS) of 14.95 mV/dec. This paper compares the analog and radio of frequency (RF) parameters of this device with those of a conventional doping-less TFET (DLTFET), including the transconductance ($g_{{\mathrm{m}}}$), transconductance-to-drain-current ratio $(g_\mathrm{m}/I_\mathrm{D})$, output conductance $(g_\mathrm{d})$, intrinsic gain ($A_{{\mathrm{V}}}$), early voltage ($V_{{\mathrm{EA}}}$), total gate capacitance ($C_{{\mathrm{gg}}}$), and unity-gain frequency ($f_{{\mathrm{T}}}$). Based on the simulated results, the $\hbox {Si}_{0.55}\hbox {Ge}_{0.45}$-source DLTFET is found to offer superior analog as well as RF performance.