SiGe Heterojunction FinFET Towards Tera-Hertz Applications

In this work, a novel structure FinFET having an ultra-thin SiGe shell channel forming a heterojunction with Si core is proposed and characterized, with an emphasis on high-speed operation capability in the tera-hertz (THz) regime, by 3-dimensional (3-D) device simulation. The proposed device is operated in the p-type enhancement mode and the ultra-thin SiGe channel confines the mobile holes very effectively by the help of the valence band offset (VBO) between SiGe channel and Si core. The simulations with multiple drift and diffusion models and quantum mechanical models for higher accuracy allow to predict the minimum channel thickness and Ge content of 2 nm and 40%, respectively, for suppressing the hole leakage outflowing over the VBO. Also, scalability was checked down to 5 nm for achieving the upcoming logic technology nodes. Cut-off frequency (f_T) and maximum oscillation frequency (f_max) are obtained to be 240 GHz and 1.04 THz at a low drive voltage as −0.7 V, respectively.