Heterojunction (SiGe/Si) triple metal dual gate extended source tunnel FET for improved DC, noise and linearity performance

Abstract

In this paper, a 2-D model of a hetero-triple metal dual gate extended source tunnel FET (TMDG-ES-TFET) is analyzed. The device features a heterojunction (HJ) designed by silicon germanium (SiGe) and Si materials in the source-channel junction and a hetero-dielectric gate stack (GS) using dielectric as silicon dioxide (SiO₂) and hafnium dioxide (HfO₂). In this research, the DC characteristics, linearity, and noise performance have been investigated. In structure the entire source region over the oxide layer has been overlapped by three distinct metals with various work functions. The paper has also investigated the impact of increasing source width (80 nm and 120 nm) over the channel. The SiGe is used as a source thereby improving the I_ON/I_OFF value and threshold voltage (V_th). The structure has a greater I_ON/I_OFF reflected as 9.1 × 10¹², a lower sub-threshold value of 41 mV/decade, and a lower V_th of 0.58 V. A standardized SILVACO technology computer aided design (TCAD) is used for the simulation. Additionally, the linearity analysis was performed as a figure of merit (FOM) for a device under investigation, taking into account various parameters like 1db compression point, 2nd and 3rd -order voltage intercept points (VIP₂ and VIP₃), the 3rd -order intermodulation distortion point (IMD₃), and the third order intermodulation intercept point (IIP₃).