Ultra-Thin SiGe in the Source Modifies Performance of Thin-Film Tunneling FET

In this work, the source structure of an n-type thin-film tunneling FET is engineered to get better performance. An ultra-thin SiGe along with Si is used in the source of silicon-based TFET. Two structures are compared with conventional TFET, one, SiGe is located on the top of Si in the source and another one in reverse. Simulations approve these structures can reduce sub-threshold swing, OFF-current several times, and increase the ON-OFF ratio. Band diagram for conduction and valance bands are investigated and band to band tunneling (BTBT) generation rate is used to find better performance. We find current flows at Si in the source with the wider bandgap. Ge mole fraction of SiGe is varied and its effects on the performance of TFET are studied. The SiGe thickness for both structures is explored to obtain the best thickness for SiGe.