Lifting on-state currents for GeS-based tunneling field-effect transistors with electrode optimization

Abstract

Tunneling field-effect transistors (TFETs) arouse great enthusiasm for energy-efficient switching devices attributed to their steep subthreshold swing (SS), yet their low on-state currents (Ion) block the practical application. We study the possibility of lifting Ion for the case of GeS-based TFETs with electrode optimization using the ab initio quantum transport simulation. An apparent promotion on Ion to an amplitude of 270–410% is achieved for the optimal GeS HetJ-TFETs compared with the unstrained ML GeS TFET, where 23–58% promotion is contributed from the vdWH electrode and the left 42–77% is from the induced strain. Ion of 463 and 878 μA/μm of the optimal p-type 10-nm-Lg GeS HetJ-TFETs almost meet the International Roadmap for Device and Systems (IRDS) goals for both low-power (LP) and high-performance (HP) devices for the year 2028. Specifically, the p-type 10-nm-Lg GeS HetJ-TFETs possess the highest Ion(LP) and Ion(HP) when Ileak < 10−6 μA/μm compared with other 2D TFETs despite the material type and device architecture and own superior energy efficiency compared with 2D MOSFETs. The remarkable promotion of Ion attributes to the narrower bandgap and larger density of states of the vdWH electrode. Our findings will promote future development for 2D HetJ-TFETs.