High Frequency Performance Of Carbon Based Semiconductor Devices

With higher carrier mobility, higher carrier concentration,higher thermal conductivity and other excellent properties, fullerene,carbon nanotube, graphene, SiC and other carbon based semiconductorscan be made as high power, high temperature resistant and highfrequency devices. The carbon based semiconductor high frequencydevices which were widely applied in micro-electronics and electronicpower technology. Here, the models of bilayer graphene high frequencyfield effect transistor (BLGFET) and4H-SiC p~+-n-n~+diode were designedin this paper, the high frequency electronic properties of the devices wereanalyzed via MATLAB numerical simulation.First, the electronic properties of BLGFET were investigated.The channel carrier type, concentration, drain current, transconductanceand cut-off frequency change with the top gate Dirac point voltage, whichwere due to the characteristic of bipolar carriers in BLGFET. The deviceperformances relate closely to the channel length and carrier mobility.Optimizing operation conditions of the BLGFET, the frequency can reachup to210GHz, which indicates that the bilayer graphene FET would besuitable for high frequency applications.Then, the forward and reverse recovery characteristics of4H-SiC p~+-n-n~+diode were analyzed. The results show that the forwardand reverse recovery characteristics of4H-SiC p~+-n-n~+diode are sensitiveto minority carrier lifetime in the region of p~+and n~+, base width, dopingdensity of base, active accptor/donor density of p~+/n~+and other conditions.The reverse recovery time of4H-SiC p~+-n-n~+diode is about10ns. Thefrequency is close to100GHz when the open circuit voltage is-200V, so4H-SiC p~+-n-n~+diode has the performance of high frequency.