ABSTRACT
One way to eliminate the ambipolar conduction of TFETs is to adopt asymmetric source and drain structure. The transfer characteristics of symmetric and three different designs of asymmetric source-drain DG TFET are compared [12]. The three asymmetric strained-Ge (s-Ge) DG TFET configurations to be discussed are an underlapped drain, a low drain-doping, and a lateral heterostructure of a largebandgap material, as shown in Figure 7.5 [12]. The general objective of adopting the asymmetric source and drain structure is to achieve a high tunneling rate at the source-end and a low tunneling rate at the drain-end in order to maintain a high on-current and a low offcurrent (leakage current).
