Over 3000 cm2V−1s−1room temperature two-dimensional electron gas mobility by annealing Ni/Al deposited on AlGaN/GaN heterostructures

We investigated sheet electron density ( n s ) and electron mobility (μ) in AlGaN/GaN heterostructures deposited with Ni/Al by annealing in vacuum. We observed that both n s and μ at room temperature increased by annealing at 1020 K and the amount of increase depended on the Ni/Al stack thickness. We achieved a room temperature Hall electron mobility of 3050 cm 2 V −1 s −1 , which is the highest value ever reported for AlGaN/GaN heterostructures. The origin of n s increase was attributed to the additionally induced tensile strain in AlGaN layer, which was confirmed by Raman spectroscopy.