Effect of Pocket Doping and Annealing Schemes on the Source-Pocket Tunnel Field-Effect Transistor

Low operating power is an important concern for sub-45-nm CMOS integrated circuits. Scaling of devices to below 45 nm leads to an increase in active power dissipation (CV².f) and subthreshold power (I_OFF.V_DD)Hence, new device innovations are being explored to address these problems. In this paper, we simulate and experimentally investigate the source-pocket tunnel field-effect transistor (TFET), which is based on the principle of band-to-band tunneling, p-i-n and source-pocket TFETs are fabricated with different pocket conditions to observe the effect of the source-side pocket on device performance. Different annealing schemes (spike and conventional rapid thermal annealing) are used to study the effect of annealing conditions on TFET performance. The source-pocket TFET shows a higher I_ON (~10 times) and steeper subthreshold swing as compared to a p-i-n TFET. The ambipolar conduction is also reduced by using a low-doped drain extension. Low-temperature measurements of the source-pocket TFET were performed, and the subthreshold swing of the source-pocket TFET shows very little temperature dependence, which confirms the dominant source injection mechanism to be band-to-band tunneling.