Performance Investigation of Source Extension Approach on III–V Vertical Tunnel FET

Abstract

A triple-metal-gate stacked III–V vertical tunnel field-effect transistor (TM-GS-VTFET) structure is examined. There are two different TM-GS-VTFETs: Device-A, which uses a source pocket, and Device-B, which uses a new source extension approach. Source pocket-engaged TFETs are recognized for their enhanced ON-state current (ION) and subthreshold swing compared to traditional TFETs. However, they may require more complex fabrication procedures. The source extension strategy alters the electric-field distribution and decreases the tunneling barrier width near the source side. This boosts the tunneling rate and increases the device functioning. The simulation was performed using the Silvaco Technology Computer-Aided Design (TCAD) tool. Various analog and radio-frequency (RF) parameters were examined. The ION in Device-B was found to be $234.03~\mu \text{A}/\mu \text{m}$ , the OFF-state current (IOFF) was $1.52\times 10^{\mathrm {-14}}\text{A}/\mu \text{m}$ , Sub-threshold swing (SS) was 28.58 mV/decade, and the transconductance (gm) was $245.28~\mu \text{S}/\mu \text{m}$ . The RF frequency parameter such as cutoff frequency (fT), oscillating frequency (fmax), and Gain Bandwidth Product (GBP) were 152.45 GHz, 830 GHz and 25.16 GHz respectively. It was observed that Device-B exhibited 11 times higher ION, 3.2 times higher GBP, and 3.15 times higher fmax than Device-A. The utilization of this source extension technique has proven to be advantageous for achieving enhanced analog and RF properties in TFETs.

Keywords

• TFET
• stacked gate
• source extension
• source pocket
• tunneling
• GaSb