Impact of Charge Balance on Static and Dynamic Characteristics of GaN Super-Heterojunction Schottky Barrier Diodes

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 ${R}_{\textit {ON}}$ 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 ${R}_{\textit {ON}}$ 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.