Improvement of C-shaped pocket TFET with sandwiched drain for ambipolar performance and analog/RF performance

A novel structure of tunneling field effect transistor device (CSP-SD-TFET) is proposed, which adds a sandwiched drain to the C-shaped pocket TFET (CSP-TFET). This structure can increase the resistance of the drain, share the lateral electric field at the tunneling junction between the channel and the drain, reduce the lateral electric field at the tunneling junction, and suppress the generation of ambipolar current. The DC and analog/RF characteristics of CSP-SD-TFET are simulated and analyzed by Sentaurus TCAD, and the sandwiched structure parameters of the drain are optimized. The results show that the sandwiched drain structure suppresses the ambipolar current and on-state current, so the parameters of the sandwiched drain structure need to be a compromise between low ambipolar current and high on-state current. The optimized CSP-SD-TFET device has good DC characteristics, such as low average subthreshold swing SS_avg (12.2mV/dec), high on/off current ratio I_on/I_off (2.5 × 10¹¹), high on-state current I_on (9.02 × 10⁻⁴ A/μm) and low ambipolar current I_amb (5.41 × 10⁻¹⁷A/μm). The RF performance of the CSP-SD-TFET, such as the cut-off frequency f_T (1 × 10¹¹ Hz) and gain-bandwidth product GBP (5.66 × 10¹⁰ Hz), are improved. It can be seen that the CSP-SD-TFET device not only has good DC characteristics but also improves analog/RF characteristics.