Comparative study of dopant-segregated Schottky barrier germanium nanowire transistors

Abstract

P-type Schottky barrier Ge nanowire transistors modulated with dopant segregated regions are proposed and studied. The impact of dopant segregated regions on device performance is simulated and investigated with numerical tools. It is revealed that dopant segregation is beneficial to increasing drive current and better utilizing nanowire channel. The OFF-state current is effectively suppressed with high dopant concentration, and the phenomena in the minimum current curves are carefully reinterpreted with carrier transport mechanisms. It is also shown that the dopant segregated regions with moderate length and high concentration can achieve high ON/OFF ratio and low subthreshold slope. Furthermore, we find that the subthreshold slope of long segregation length is insensitive to source/drain barrier heights, and that moderate segregation length helps to obtain lower subthreshold slope as channel length is scaled down.

Simulation and comparative study of tunneling field effect transistors with dopant-segregated Schottky source/drain

“…This is because when N seg is low, the DS regions of STFET can be easily depleted with a small L seg , thus showing lower I on and larger SS. 38) It also shows when the width is larger than a certain value to maintain PD, BTBT is irrelevant to the width of highly doped regions.…”

“…So when reaching thermal equilibrium, the DS at source is more likely to be partially depleted (PD). 37,38) The potential change rate at source= channel interface would be as high as that of TFET, and there would be more BTBT current, thus showing better switching characteristics. The electron SB at source is also thicker, which suppresses SBE and SBT current.…”