Graphenic Carbon-Silicon Contacts for Reliability Improvement of Metal-Silicon Junctions

TL;DR

This paper demonstrates that graphenic carbon-silicon contacts offer a highly reliable alternative to titanium silicide contacts in silicon devices, significantly improving stability under high current stress and maintaining low Schottky barrier height.

Contribution

The study introduces a graphenic carbon contact method for silicon that surpasses TiSi in reliability and stability, with potential for high-temperature applications.

Findings

C-Si contacts have a Schottky barrier of 0.45 eV, similar to TiSi.

C-Si contacts are over 100 million times more stable under high current stress.

Potential for ultra-low, high-temperature stable contact resistance.

Abstract

Contact resistance and thermal degradation of metal-silicon contacts are challenges in nanoscale CMOS as well as in power device applications. Titanium silicide (TiSi) contacts are commonly used metal-silicon contacts, but are known to diffuse into the active region under high current stress. In this paper we show that a graphenic carbon (C) contact deposited on n-type silicon (C-Si) by CVD, has the same low Schottky barrier height of 0.45 eV as TiSi, but a much improved reliability against high current stress. The C-Si contact is over 100 million times more stable against high current stress pulses than the conventionally used TiSi junction. The C-Si contact properties even show promise to establish an ultra-low, high temperature stable contact resistance. The finding has important consequences for the enhancement of reliability in power devices as well as in Schottky-diodes and electrical contacts to silicon in general.