Improved drain current characteristics of tunnel field effect transistor with heterodielectric stacked structure

Abstract

In this paper, we proposed a 2-D analytical model for electrical characteristics such as surface potential, electric field and drain current of Silicon-on-Insulator Tunnel Field Effect Transistor (SOI TFETs) with a SiO₂/High-k stacked gate-oxide structure. By using superposition principle with suitable boundary conditions, the Poisson's equation has been solved to model the channel region potential. The modeled channel potential is to calculate both vertical and lateral electric field. 2-D Kane's model is used to calculate the drain current of TFET and the expression is taken out by analytically integrating the band-to-band tunneling generation rate over the thickness of channel region. The device is modeled in variation with different device parameters like channel length (L_CH), dielectric thickness (t_ox), silicon thickness (t_si) and input voltage (V_dsand V_gs). Also, the comparison of SiO₂ and stacked high k dielectric TFET is obtained. It has been found from the presented results that the hetero-dielectric stacked TFET structure provides ON current 10^-6A/um. However, SiO₂ dielectric structure provides the ON current of 10^-8A/um. The proposed model is validated by comparing it with Technology Computer-Aided Design (TCAD) simulation results obtained by using SILVACO ATLAS device simulation software.