P+-Ge1−xSnx / p−-Ge1−x−ySixSny / n-Ge1−x−ySixSny NTFET analysis and the realization of n-Ge1−x−ySixSny ohmic contact

Abstract

In this paper, n-Ge1-x-ySixSny ternary alloy was successfully grown by using the Sb in situ doping technique through sputter epitaxy method. Ohmic contacts to n-Ge1-x-ySixSny are realized by shallow P implant. Group IV heterostructure p⁺-Ge_1-xSn_x / p^--Ge_1-x-ySi_xSn_y / n-Ge_1-x-ySi_xSn_y N-channel tunneling field-effect transistor (NTFET) is proposed and simulated. The narrow bandgap of Ge_1-xSn_x increases the band-to-band-tunneling (BTBT) tunneling probability at Γ valley, which leads to a higher on-state current. The n-Ge_1-x-ySi_xSn_y is used as drain since it exhibits a large indirect bandgap, which reduces the ambipolar behavior in NTFET.