The impact of scaled channel length in tunneling field effect transistors (TFETs)

In this paper, we investigate the channel length (L_CH) of the silicon-on-insulator (SOI) n-type tunneling field effect transistor (NTFET) with the respect of device performance. 2D-device simulation was used for simulating the devices with 30 nm gate length of SOI NTFET with 10 nm thin buried oxide (t_BOX) and 7 nm thin silicon body (t_si). The device performance, such as threshold voltage (V_TH), ON current (I_ON), OFF current (I_OFF), and subthreshold swing (SS) was extracted from the current-voltage characterizations of SOI NTFET. The longer the channel length, the lower the SS value and I_ON/I_OFF ratio obtained in these simulations. Unfortunately, the SS values obtained throughout these simulations were still higher than the typical SS value of TFET device which is supposed to be lower than 60 mV/decade. However, the SS values obtained was still lower compared to the SS value of the MOSFET. On the other hand, I_ON/I_OFF ratio still high which is better for switching operation of the devices.