Low-temperature-deposited AlGaN interlayer for improvement of AlGaN/GaN heterostructure

Abstract We have studied the effect of a low-temperature-deposited (LT-) AlGaN interlayer on AlGaN/GaN heterostructure. High-crystalline-quality and crack-free AlGaN layers covering the entire compositional range were realized using the LT-AlN interlayer. We also showed that AlGaN is applicable as the LT-interlayer under the condition that the AlN molar fraction of the LT-AlGaN interlayer is equal to or larger than that of the overgrown AlGaN layer. Furthermore, electrically conductive LT-Al 0.1 Ga 0.9 N has been realized with an intermediate deposition temperature and very high SiH 4 flow rate, in addition to the high-quality overgrown AlGaN layer. It is thought that the LT-interlayer technology can overcome the challenges of growing a high-quality AlGaN layer with high AlN mole fraction on GaN layers.