Impact of spacer-drain workfunction engineered on the characteristics of a Si-Ge dopingless tunnel field effect transistor with lower subthreshold swing

Abstract

The impact of spacer and dual metal drain on Subthreshold Swing (SS) and ON current of the dopingless TFETs have been examined in this paper using Si and Ge as channel material. In the proposed device spacers are used on either side of the drain and source regions with a dielectric constant of 22, i.e., Hafnium oxide (HfO 2 ) of length 15 nm and 5 nm respectively. Source and drain region are formed using charge plasma concept in the proposed device because it was based on dopingless technology. We use dual metal on drain electrode to creating a potential barrier to restricting the tunneling of holes when the negative gate voltage applied. Therefore, the proposed device offers high I ON /I OFF ratio of 1011, smaller point SS of 37 mV/decade and average SS of mV/decade etc. We have also measure spacer effect between the proposed device and dual metal drain (DMD) dopingless double gate TFETs without spacer.