Performance evaluation of graphene nanoribbon-based differential amplifier

Abstract

The evolution of transistor for many device applications have been following the Moore’s Law prediction. The downsizing of transistor to meet design specification may lead to numerous issues related to short channel effect such as leakage current, tunnel effect and increase in power dissipation. To mitigate these issues, nanomaterial is proposed to replace silicon as one of the potential solution. Graphene is an alternative material with its high mobility and high thermal conductivity. Nanoribbon is etched in graphene to convert its metal properties to semiconductor. In this research, differential amplifier is constructed based on graphene device. The performance of graphene based differential amplifier is then compared with silicon-based material for L=32nm. This study used HSPICE for circuit construction and simulation with established graphene nanoribbon SPICE model. Current mirror concept is applied at load of differential amplifier. The number of ribbons is set as 6 and graphene dimer line, N is varied to evaluate performance in term of differential mode gain, common mode gain and CMRR. From simulation result, the highest differential mode gain is 2.59 at N=19 and the lowest common mode gain is 0.12 at N=9. GNRFET based differential amplifier has the best performance with highest CMRR of 18.05 at N=19. While comparing with Si-MOSFET based differential amplifier, GNRFET based differential amplifier is 11.16% higher in differential mode gain, 39.13% lower in common mode gain and 82.14% higher in CMRR. Hence, GNRFET based differential amplifier is 82.14% better performance than Si-MOSFET based differential amplifier. The outcome of this study can be guideline for future study on circuit implementation using graphene material.