The Structural Performance of a Novel Double‐Stacked Heterogeneous Gate Heterojunction Tunneling Field‐Effect Transistor

Abstract

In this work, an original Si/SiGe heterojunction tunneling field‐effect transistor which has a double‐stacked heterogeneous oxide gate (HfO2/Al2O3) structure (DSG–HJ–TFET) is designed and investigated by Sentaurus technology computer aided design (TCAD) simulation software. To ensure good interface quality, a stacked oxide gate dielectric of Al2O3 and HfO2 is proposed. The on‐state current (Ion) is increased though improving the carrier mobility degradation caused by the poor quality of interface between the high‐κ dielectric and semiconductor. Moreover, a heterojunction with SiGe (source)/Si (channel) and pocket layer which is inserted between the source region and the channel is adopted to reduce the tunneling barrier and improve the Ion. Therefore, the higher Ion is obtained by the proposed DSG–HJ–TFET. In the simulation results, it is shown that Ion of DSG–HJ–TFET is increased by three orders of magnitude compared with that of the conventional high‐κ gate dielectric TFET structure. In addition, the off‐state current (Ioff) of 4.91 × 10−11 μA μm−1, the minimum subthreshold swing of 14 mV dec−1, the Ion/Ioff ratio of 1.13 × 1012, transconductance of 260 μS μm−1, fT of 49.8 GHz, and gain bandwidth product (GBW) of 7.2 GHz are obtained. The propose DSG–HJ–TFET is favored in ultralow‐power applications for the rather good performance.