Titanium Contacts to Graphene: Process-Induced Variability in Electronic and Thermal Transport

TL;DR

This study investigates how process parameters influence the composition, electrical contact resistance, and thermal transport at titanium-graphene interfaces, revealing tunable contact properties through deposition conditions and their impact on device performance.

Contribution

It demonstrates the correlation between Ti contact composition and contact resistance, showing how deposition parameters affect interface quality and thermal conductance in graphene devices.

Findings

Contact composition correlates linearly with contact resistance.

Deposition rate and base pressure influence contact composition.

Higher oxide content interfaces have lower thermal boundary conductance.

Abstract

Contact Resistance (RC) is a major limiting factor in the performance of graphene devices. RC is sensitive to the quality of the interface and the composition of the contact, which are affected by the graphene transfer process and contact deposition conditions. In this work, a linear correlation is observed between the composition of Ti contacts, characterized by X-ray photoelectron spectroscopy, and the Ti/graphene (Gr) contact resistance measured by the transfer length method. We find that contact composition is tunable via deposition rate and base pressure. Reactor base pressure is found to effect the resultant contact resistance. The effect of contact deposition conditions on thermal transport measured by time-domain thermoreflectance is also reported and interfaces with higher oxide composition appear to result in a lower thermal boundary conductance. Possible origins of this thermal boundary conductance change with oxide composition are discussed.