The impact of interfacial Si contamination on GaN-on-GaN regrowth for high power vertical devices

The development of gallium nitride (GaN) power devices requires a reliable selective-area doping process, which is difficult to achieve because of ongoing challenges associated with the required etch-then-regrow process. The presence of silicon (Si) impurities of unclear physical origin at the GaN regrowth interface has proven to be a major bottleneck. This paper investigates the origin of Si contamination at the epitaxial GaN-on-GaN interface and demonstrates an approach that markedly reduces its impact on device performance. An optimized dry-etching approach combined with UV-ozone and chemical etching is shown to greatly reduce the Si concentration levels at the regrowth interface, and a significant improvement in a reverse leakage current in vertical GaN-based p-n diodes is achieved. Published under an exclusive license by AIP Publishing.

Automated summary

The paper investigates the silicon (Si) contamination issue in gallium nitride (GaN) power devices and presents an approach to reduce its impact on device performance. Through optimized etching methods and chemical treatment, the silicon concentration levels at the regrowth interface can be effectively lowered, leading to improved performance in vertical GaN-based p-n diodes.