Optimisation of 4H-SiC MOSFET Structures for Logic Applications

Although Silicon Carbide has become the material of choice for high power applications in a range of extreme environments, the interest in creating active chemical sensors requires the development of transistors for additional control circuits to operate in these environments. Despite the recent advances in the quality of oxide layers on SiC, the mobility of inversion layers is still low and this will affect the maximum frequency of the operation for these devices. We present simulation results which indicate that a delta channel, in both n-channel and p-channel structures, is suitable for transistors used with these low level signals. By varying the doping levels of the device we have shown that the optimum delta doping for this application is 1.43x1019 cm-3 for both n and p channel devices. We then show the effects of high temperatures on the delta FET devices and make comparisons with standard SiC MOSFET devices.