First demonstration of RF N-polar GaN MIS-HEMTs grown on bulk GaN using PAMBE

• Published in: Semiconductor science and technology Vol. 34; no. 4; pp. 45009 - 45013
• Main Authors: Pasayat, Shubhra S, Ahmadi, Elaheh, Romanczyk, Brian, Koksaldi, Onur, Agarwal, Anchal, Guidry, Matthew, Gupta, Chirag, Wurm, Christian, Keller, Stacia, Mishra, Umesh K
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.04.2019
• Subjects: gallium nitride; high electron mobility transistor; power amplifier
• ISSN: 0268-1242; 1361-6641
• DOI: 10.1088/1361-6641/ab0761

Nitrogen polar (N-Polar) GaN high-electron mobility transistors (HEMT) targeting high efficiency in millimeter wave power amplification applications were fabricated on epitaxial layers grown by plasma assisted molecular beam epitaxy (PAMBE) on on-axis semi-insulating bulk GaN substrates. On-state current density of ∼1 A mm−1 was observed on transistors with LG = 0.75 m, LGS = 0.5 m and LGD = 3.75 m. In a deep class AB mode of operation, devices fabricated on epitaxial structures with these substrates demonstrated 60% higher electron channel mobility compared to devices fabricated with a similar epitaxial structure grown on sapphire substrates using metal-organic chemical vapor deposition. As the first demonstration of N-polar GaN-on-GaN MISHEMT for power amplifier applications, the devices discussed in this letter bridge a path towards achieving higher power gain and efficiency for millimeter-wave N-polar GaN HEMTs.