Performance Evaluation of Novel Strain-Engineered Ge-InGaAs Heterojunction Tunnel Field-Effect Transistors (original) (raw)

Novel strain-engineered staggered gap Ge/In x Ga 1−x As heterojunction tunnel FETs (H-TFETs) are proposed and theoretically evaluated. Modulation of the indium alloy composition at the source-channel heterointerface resulted in 18.6× and 16.9× enhancement in I ON for n-and p-channel Ge/In x Ga 1−x As H-TFETs, respectively, as compared with strained Ge homojunction TFETs (p +-Ge/i-Ge/n +-Ge). The n-type H-TFETs (p +-Ge/i-In x Ga 1−x As/n +-In x Ga 1−x As) exhibited superior leakage suppression due to a larger tunneling barrier at the channel-drain interface. Moreover, the p-type H-TFETs (n +-In x Ga 1−x As/i-Ge/p +-Ge) demonstrated a significant enhancement in I ON due to an unequal shift in the conduction band edge as a result of doping-induced bandgap narrowing. The simulated tensile-strained Ge/In x Ga 1−x As H-TFETs show a great promise for ultralow-power switches with high ON-state and low OFF-state current, providing a new path for low-power complimentary TFET logic.