Ohmic contacts for AlGaN/GaN HEMTs with artificially introduced uneven structures at metal/AlGaN interfaces

A new approach to reduce contact resistance on AlGaN/GaN HEMTs, in which an inherent tradeoff involving the AlGaN layer thickness exists, is discussed. This method introduced uneven AlGaN layer structures under the ohmic contact metal layers. The fringing effect where the AlGaN layer thickness fluctuates plays an important role. Effects of horizontal pattern features and their size, in other words, pattern density were investigated.