Fabrication of graphene-on-GaN vertical transistors

Abstract

The excellent transport properties of graphene make it an excellent option for very high frequency electronics. However, the poor output resistance and difficult lithography of lateral transistors significantly limit its performance. In this thesis, we propose a new kind of vertical graphene base transistor to take advantage of both wide bandgap GaN semiconductors and zero bandgap graphene for high frequency transistors. This majority-carrier device has a metal collector, a graphene base and an AlGaN/GaN emitter. The first device prototype exhibits very promising current density(~mA/cm 2 ) and current gain ([alpha] ~ 50 %). Simulations further support that with proper optimization of the materials and device structure, the proposed transistor can be a promising candidate for future high frequency applications.