Improvement of drain current of AlGaN/GaN-HEMT through the modification of negative differential conductance (NDC), current collapse, self-heating and optimization of double hetero structure

For the high-power application, high breakdown voltage of the HEMT device is required that is free from the negative effects such as current collapse and NDC. In this paper, it is found that without any substrate for the higher dimension, the breakdown is larger than the lower dimension. However, it is not free from NDC, which can be eliminated by the shorter channel. Back barrier layer is used to increase this breakdown voltage for the shorter dimension which has given very efficient result, doubling the voltage from 6 V to 13 V for the ‘x’ composition of 0.3 of AlxGa1−xN and 16 V for AlN back barrier. At the end, the relation of capacitance to the breakdown voltage for the shorter channel is derived, which shows that the breakdown voltage is mostly dependent on the carrier concentration in the lower layer.