Optimization of Graded AlInN/AlN/GaN HEMT Device Performance Based on Quaternary Back Barrier for High Power Application

Abstract

Conventional HEMT devices perform poorly especially in the Ka band due to buffer electron spillage and poor confinement. Microwave and defense industries are key consumers of electronics and require transistors to be free from adverse effects namely current collapse in the drain for elevated power application. This work investigates the effects of graded AlInN barrier together with emerging quaternary material on device output in providing an alternate solution to industrial needs. The Aluminum mole fraction had been linearly increased along the graded section, with the addition of the AlInGaN back barrier. Improved current density and electric field demonstrate potential for high linearity application. The back barrier improves electron confinement in the channel while the effect of graded barrier was found to enhance output and transfer characteristics where the former incremented by almost 60% and the latter by around 1.9 A/mm, compared to conventional devices. Concentration of 2-dimensional electron gas (2DEG) had elevated by four times in the channel region with speed of electrons at 17.8 × 106 cms−1 in the back barrier. Overall, it has been demonstrated that the optimized AlInN/GaN-based HEMT shows excellent electrical characteristics and is a promising alternative to AlGaN/GaN HEMT for high frequency and high power application.