Contact Resistance Induced Variability in Graphene Field Effect Transistors

The success of the graphene field-effect transistor (GFET) is primarily based on solving the problems associated with the growth and transfer of high-quality graphene, the deposition of dielectrics and contact resistance. The contact resistance between graphene and metal electrodes is crucial for the achievement of high-performance graphene devices. This is because process variability is inherent in semiconductor device manufacturing. Two units, even manufactured in the same batch, never show identical characteristics. Therefore, it is imperative that the effect of variability be studied with a view to obtain equivalent performance from similar devices. In this study, we undertake the variability of source and drain contact resistances and their effects on the performance of GFET. For this we have used a simulation method developed by us. The results show that the DC characteristics of GFET are highly dependent on the channel resistance. Also the ambipolar characteristics are strongly affected by the variation of source and drain resistances. We have captured their impact on the output as well as transfer characteristics of a dual gate GFET.