Burying Impurities And Defects In Regrown III-Nitride Structures
Tech ID: 31870 / UC Case 2020-081-0
Certain III-nitride device architectures require ex-situ selective-area doping or growth. In special applications, it is necessary to transfer epitaxial layers between two reactors to meet the needs of their complex geometries. This atmospheric exposure causes interfacial impurities that reduce device performance. Prior to regrowth, certain geometries also require dry etching, which introduces significant damage to the epilayer. The combined detriments of interface impurities and etching-induced damage are adverse to final device performance.
Researchers at the University of California, Santa Barbara have eliminated the effects of interfacial impurities and/or dry etching-induced damage by burying the defects at the regrown junction. The p-n diode structure is inverted to form a p-down structure and a p-GaN spacer layer is introduced prior to the growth of the junction. Due to significantly larger doping levels in the p-side compared to the n-side, the depletion width on the p-side is far less than the n-side. This method is more controllable and industrially-viable compared to alternative ex-situ methods. It can be performed in many growth processes, including plasma-assisted MBE, ammonia MBE, MOCVD and other CVD methods. It also provides a viable path to selective-area doping for complex geometry electronic and optoelectronic devices such as JFETs and CAVETs without the need for complicated processes like ion-implantation.
- Eliminates interfacial impurities
- Reduces epilayer damage
- Power Electronics