The suppression of background doping in selective area growth technique for high performance normally-off AlGaN/GaN MOSFET

摘要

In this paper, the selective area growth (SAG) technique is used to regrow thin AlGaN/GaN heterostructure on access region for realizing trench gate normally-off AlGaN/ GaN MOSFET. Heavy background doping is found in SAG AlGaN/GaN heterostructure, which is not expected for its degradation on device performance. The background doping originates from SiO_2 residuals at SAG interface. Through reducing the deposition temperature of SiO_2 mask, background doping can be efficiently suppressed. As a result, the 2 dimensional electron gas transport property of SAG AlGaN/ GaN heterostructure improves greatly, which is as good as the as-grown AlGaN/GaN heterostructure. Moreover, the performance of normally-off SAG AlGaN/GaN MOSFET improves greatly by suppression the Si residual on GaN template.