Hetero-gate-Dielectric Symmetric U-shaped gate tunnel FET

Heterogeneous gate dielectric is used in a nanoscale symmetric U-shaped gate tunnel FET (SUTFET), which resulted in ION, IOFF, subthreshold swing (SS), and Iambipolar enhancement. ION of 1.5 × 10−5 A/μm, IOFF of 6 × 10−12 A/μm, average subthreshold swing of (SS) 19.83 mV/decade from 0 V < VGS < VThreshold, and Iambipolar of 5 × 10−9 A/μm are obtained by using high-k dielectric close to the source and low-k dielectric in the vicinity of drain. The gate dielectric engineering shows characteristic enhancement in compare to SUTFET with single gate dielectric material. The strong coupling between the gate and transistor channel near the source results in reduced potential barrier width in tunnel junction, which leads to higher ION and lower subthreshold swing. Moreover, the presence of low-k dielectric near the drain reduces ambipolar current by increasing potential barrier height. This improved SUTFET characteristics makes it suitable for the usage in digital circuits due to reduced ambipolar response.