Etched-and-Regrown GaN pn-Diodes With 1600 V Blocking Voltage

• Published in: IEEE journal of the Electron Devices Society 2021-01, Vol.9, p.318-323
• Main Authors: Armstrong, Andrew M., Allerman, Andrew A., Pickrell, Greg W., Crawford, Mary H., Glaser, Caleb E., Smith, Trevor
• Format: Article
• Language: English
• Subjects: Chemicals; Current leakage; Diodes; Electric potential; ENGINEERING; Epitaxial growth; Etching; Forward characteristics; Gallium nitride; Gallium nitrides; Inductively coupled plasma; Junctions; Metalorganic chemical vapor deposition; Organic chemicals; Organic chemistry; p-n junctions; Plasma etching; Plasmas; power semiconductor devices; Substrates; Surface treatment; Voltage
• ISSN: 2168-6734; 2168-6734
• DOI: 10.1109/JEDS.2021.3061028

Etched-and-regrown GaN pn-diodes capable of high breakdown voltage (1610 V), low reverse current leakage (1 nA = 6 \mu \text{A} /cm 2 at 1250 V), excellent forward characteristics (ideality factor ~1.6), and low specific on-resistance (1.1 \text{m}\Omega .cm 2 ) were realized by mitigating plasma etch-related defects at the regrown interface. Epitaxial {n} -GaN layers grown by metal-organic chemical vapor deposition on free-standing GaN substrates were etched using inductively coupled plasma etching (ICP), and we demonstrate that a slow reactive ion etch (RIE) prior to {p} -GaN regrowth dramatically increases diode electrical performance compared to wet chemical surface treatments. Etched-and-regrown diodes without a junction termination extension (JTE) were characterized to compare diode performance using the post-ICP RIE method with prior studies of other post-ICP treatments. Then, etched-and-regrown diodes using the post-ICP RIE etch steps prior to regrowth were fabricated with a multi-step JTE to demonstrate kV-class operation.