Performance Analysis of a Steep-Slope Bi-channel GaSb-GaAs Extended Source Tunnel Field Effect Transistor with Enhanced Band-to-Band Tunneling Current

This paper presents a comprehensive investigation of the electrical properties of a heterojunction tunnel field effect transistor with enhanced electrical tunneling current. The proposed device structure incorporates an extended source region and two parallel channels positioned above and below the source region. This configuration effectively amplifies the tunneling area, leading to a significant improvement in the on-state current. Moreover, the inclusion of an embedded oxide region between the source and drain regions confers the device with a high resistance to short channel effects. The combination of materials in both the source and channel region results in a staggered band alignment at the tunneling junction. This specific configuration leads to a lower threshold voltage for the initiation of tunneling. The impact of critical design parameters on the device performance has been thoroughly examined. A 2D variation matrix has been developed to compute the threshold voltage and on-state current variation based on the source doping density and gate workfunction, which serve as essential design parameters to optimize the electrical performance of the device. Furthermore, the device has achieved a unity current-ratio frequency of 300 GHz indicating its suitability for high-frequency applications. Additionally, the proposed structure provides an on-state current of 2.24×10-4 (A/µm), an off-state current of 1.24×10-15 (A/µm), an on/off current ratio of 1.81×1011, and a subthreshold swing of 5 (mV/dec). These characteristics make the device viable for energy-efficient, high-speed digital circuits.