Influence of AlGaN and InGaN Back Barriers on the Performance of AlGaN/GaN HEMT

This paper does a comparative analysis of the effect of AlGaN and InGaN back barriers on the current and breakdown voltage characteristics of Al0.25Ga0.75N/GaN high electron mobility transistors (HEMTs) grown on sapphire substrates. Compared with the conventional GaN HEMTs, the introduction of a back barrier significantly improves the breakdown voltage values due to better confinement, while the maximum current decreases due to reduced sheet electron density. The paper also illustrates the effect of varying thickness of the back barrier with a 100-µm gate width and a uniform Lgd of 1 µm. A maximum breakdown voltage of 390 V has been observed for AlGaN back barrier integrated structures as compared with InGaN back barrier integrated structures, which show a maximum breakdown voltage of 225 V.