Simulation of the Germanium-Tin Tunneling Field-Effect Transistors with a Ge Cap Layer: Improved Subthreshold Swing and I_on/I_off Ratio

摘要

Germanium-tin tunneling field-effect transistors (GeSn TFETs) with a Ge cap layer are comprehensively investigated by numerical device simulations. Inserting an ultrathin Ge cap layer between the high-k dielectric and the GeSn alloy aids the improvement of device performance owing to the better interface characteristics and the suppressed leakage current. The improved subthreshold characteristic is beneficial for enhancing the device performance at low supply voltages. The ultrathin Ge cap layer may be needed for the future high-performance GeSn TFETs applications.