Improvement of current drivability in high-scalable tunnel field-effect transistors with CMOS compatible self-aligned process
Two strategies are introduced herein to improve current drivability of tunnel field-effect transistors (TFETs). First, gate-to-channel coupling is increased by ∼22% in terms of effective gate capacitance (C ox) with the help of hemi-cylindrical device architecture. A novel iterative corner rounding process was developed for highly reliable gate dielectric formation without field crowding at sharp corner. The second approach is change channel orientation. The 〈100〉 and 〈110〉 oriented-channel TFETs were fabricated on (100) silicon surface. Consequently, both planar and hemi-cylindrical structures show consistent results that 〈110〉 is far better than 〈100〉 for higher on-current (I on). With these two structural improvements, the 〈110〉 hemi-cylindrical TFET shows ∼30× higher I on than that of the control (i.e. 〈100〉 planar TFET).
