Wafer Scale Mapping and Statistical Analysis of Radio Frequency Characteristics in Highly Uniform CVD Graphene Transistors

Radio frequency (RF) transistor based on graphene has attracted tremendous research efforts in the past few years. Despite the fact that such material is developed on a wafer-scale level, the majority of reported high performance of individual transistors is limited to individual or a few devices. As a result, the electronic uniformity and stability study on a large number of transistors remain unexplored especially for RF performance, which are the most critical factors for any practical applications. In this work, a comprehensive statistical analysis of the uniformity of DC and RF characteristics simultaneously for hundreds of transistors fabricated from transferred large area CVD-grown graphene in a 4-inch HfSiO/Si wafer is carried out for the first time. For devices with the same gate length of 0.8 mu m, the coefficient of variation (CV) for Dirac point voltage and extrinsic peak transconductance is only 0.07 and 0.03, respectively. In addition, the intrinsic f(T)*L-g is high up to about 20 GHz.mu m, which is among the best value for the graphene RF transistors. More importantly, the CV for the as-measured f(max)/f(T) is as low as 0.11, indicating highly uniform RF characteristics across the 4-inch wafer.