The impact of donor/acceptor types of interface traps on selective buried oxide TFET characteristics

Abstract

This paper investigates the reliability of the selective buried oxide TFET δp+ silicon-germanium layer at the tunneling junction. The impact of various uniform and Gaussian trap distributions and energies on the band-to-band tunneling current has been examined. The device has been optimized for different gap positions in the buried oxide. The OFF current of the proposed device is 1.7 × 10−18 A/µm. It has been observed that the effect of Gaussian trap is more compared to that of uniform trap. The study quantifies the DC parameters such as ION/IOFF ratio, subthreshold swing against different types of interface traps (donor or acceptor), density (Dit), position (near the tunneling junction or oxide/channel interface) and trap energy level (Etrap). Drain current reduces in the presence of acceptor-type trap and the variation is more for large trap density (1 × 1014 cm−3). An opposite behavior is perceived in the presence of donor-type traps. The device with highest acceptor trap concentration (1 × 1014 cm−3) provides minimum ON current of 2.21 × 10−6 A/µm whereas in case of donor trap concentration (1 × 1014 cm−3), highest ON current of 2.93 × 10−5 A/µm is obtained. The device with no traps proves to be better by providing maximum ION/IOFF ratio of 3.89 × 1012 with SS of 45 mV/dec. Further, the affectability of quantum correction on various electrical parameters has been studied for different types of traps.