Material properties analysis of graphene base transistor (GBT) for VLSI analog circuits design

Abstract

Graphene base transistor’s (GBT) analysis has been reviewed in this paper. This study has been focused on work carried out by other authors for GBT physics. Here prominence has been given to material properties and their effects on GBT for VLSI analog circuit design to operate in high frequency range of THz. Various papers in literature have been reported for the implementation of designs with different emitter and collector materials. Materials properties are the controlling parameters to decide cut-off frequency (f­_T), trans-conductance, gain and off current (I_off) in GBT. The implemented results of literatures signify that the electron affinity and work function of emitter and collector are the dominant factors for flow of charges from emitter to collector. Dependency of these two parameters on dielectric constant and thickness of emitter-base insulator (EBI) and base collector insulator (BCI) that are tantalum pentoxide (Ta₂O₅), carbon-doped silicon oxide (SiCOH) and SiO₂ has been studied. Effects of collector and BCI thickness have been investigated in detail to scrutinize base leakage current by the virtue of back scattering in collector-BCI interface. Small signal equivalent circuit model for GBT have also been studied by including parasitic capacitance behaviour between graphene Dirac-point potential with respect to graphene fermi level, emitter, EBI, BCI and collector fermi level potential.