Graphenic carbon-silicon contacts for reliability improvement of metal-silicon junctions

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 108 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.