Impact of Charge Balance on Static and Dynamic Characteristics of GaN Super-Heterojunction Schottky Barrier Diodes
Jesse T. Kemmerling, Rian Guan, Mansura Sadek, Sundar Babu Isukapati, Woongje Sung, Sangwoo Han, Rongming Chu
Abstract
This letter reports the first controlled experimental study on the impact of charge-balance on static and dynamic characteristics of GaN super-heterojunction Schottky barrier diodes (SHJ-SBD). Charge balance between p- and n-type doped GaN for reducing peak E-field can be optimized via charge-balance etching (CBE) of the p-GaN SHJ region to improve dynamic <inline-formula> <tex-math notation="LaTeX">${R}_{\textit {ON}}$ </tex-math></inline-formula> degradation and breakdown voltage (BV). Three CBE conditions were fabricated with the same process on a single epitaxial wafer to mitigate process dependent variation. Charge-balance varied from donor-rich (thinner p-GaN) to near-optimum charge-balance condition, which enabled excellent dynamic <inline-formula> <tex-math notation="LaTeX">${R}_{\textit {ON}}$ </tex-math></inline-formula> degradation of 16.9% at 3 kV and BV greater than 10 kV without field plate. TCAD simulation reinforces understanding showing CBE effect on E-Field redistribution and reduced peak E-field.