Nitride HEMTs vs arsenides: The ultimate battle?

In this paper, we have studied the limit capabilities of nitride and arsenide HEMTs and shown that the frequency limit of these devices has already been reached. The nature of these frequency constraints arises from device design rather than from semiconductor properties. In particular we have established that the product tBCdg is the critical parameter which could not be minimized any further technologically. In summary it could be stated that nowadays InP pHEMTs offer the highest frequencies and GaN HEMTs on SiC substrate are the most powerful devices. In addition we have shown that the breakdown voltages and power density of nitride HEMTs at a given operating frequency are controlled by heterostructure barrier layer thickness, increasing with a decrease of the latter. Therefore it is necessary to develop high efficiency nitride nanoheterostructures with tB less than 10 nm. In this respect the AlN/GaN heterostructures are beyond comparison due to the good performance of 2D gas and relative simplicity of growth process.