Device Structure Modifications in Conventional Tunnel Field Effect Transistor (TFET) for Low-power Applications

With the rapid scaling of transistors in the nanometer regime, various shortchannel effects emerge in short-channel devices; researchers are looking for an alternative device to replace complementary MOSFET (CMOS) in circuit applications. TFETs are considered to be a good replacement for the conventional MOSFET in the upcoming technologies. The methods used for making ION higher also impacts the IOFF current. So, the overall current ratio remains unaltered. To overcome this problem, a technique has been developed and adopted in this work that not only improves the current ratio but also makes the subthreshold swing steeper. The major improvements are the reduction of short channel effects, enhancing current ratio reducing dynamic power consumption. Negative capacitance being a new phenomenon, helps in providing improvised results. The device optimized in this work has given values of Subthreshold swing as 53.75 mV/decade, ION and IOFF as 4.295*10-5 A/μm, 6.01*10-15 A/μm, respectively. DIBL calculated for conventional NCTFET is 61.2 mV/V, and for proposed NCTFET is 31.92 mV/V. So DIBL improvement of 52.2% has been achieved.

Keywords: Complementary MOSFET, Current ratio, Drain Induced Barrier Lowering (DIBL), ION, IOFF, Negative Capacitance, Sub-threshold swing, Tunnel Field Effect Transistor.