Contact resistance is becoming a major limitation to device performance and new strategies are required to meet the needs of next-generation devices. Existing contacts typically exploit the thermal and chemical stability of silicide/Si interfaces and take the form of a metal/silicide/Si heterostructure (e.g. W/TiN/TiSi2/Si), with the contact resistance dominated by the silicide/Si interface. The contact resistance of this interface is limited by the doping concentration in the Si substrate and the Schottky barrier height (SBH) of the heterojunction. However, doping concentrations already exceed equilibrium solid solubility limits and further increases achieve only minor improvements. Instead, any further reduction in contact resistivity relies on reducing the SBH. This project will explore methods for controlling the SBH and develop device structures for measuring ultra-low contact resistivities.
Emeritus Professor Robert Elliman, Mr Tom Ratcliff