Nonalloyed Ohmic Contacts in AlGaN/GaN HEMTs With MOCVD Regrowth of InGaN for Ka-Band Applications

Cakmak H., Ozturk M., Ozbay E., Imer B.

IEEE TRANSACTIONS ON ELECTRON DEVICES, vol.68, no.3, pp.1006-1010, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 68 Issue: 3
  • Publication Date: 2021
  • Doi Number: 10.1109/ted.2021.3050740
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Applied Science & Technology Source, Business Source Elite, Business Source Premier, Communication Abstracts, Compendex, Computer & Applied Sciences, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.1006-1010
  • Keywords: AlGaN/GaN high-electron-mobility transistor (HEMT), metal-organic chemical vapor deposition (MOCVD), regrown InGaN ohmic contacts
  • Middle East Technical University Affiliated: Yes


Low-resistance ohmic contacts in AlGaN/GaN high-electron-mobility transistor (HEMT) devices require high-temperature (HT) annealing (>800 C) which can deteriorate material quality, surface morphology, and edge acuity of the metal stacks. This article demonstrates the high-frequency and high-power performance of the AlGaN/GaN HEMT devices with low-temperature metal-organic chemical vapor deposition (MOCVD) regrown degenerately doped InGaN ohmic contacts compared with GaN-based regrown contacts. Ohmic contacts fabricated by regrowth methods could be a valuable alternative for both metal-based alloyed ohmic contacts and implantation-based ohmic contacts. Using a T-gate and MOCVD regrown InGaN ohmic contacts, the AlGaN/GaN HEMT with an L-g of 150 nm and S-D spacing of 2.5 mu m demonstrated a maximum drain current of 0.94 A/mm and a peak transconductance of 337 mS/mm. The same device exhibited a forward current gain frequency f(t) of 36.8 GHz and a maximum frequency of oscillation f(max) of 75.0 GHz. A power density of 3.07 W/mm with a 60% drain efficiency was measured at 35 GHz with a V-ds of 20 V and a quiescent current of 100 mA/mm.