Polyimide passivated AlGaN-GaN HFETs with 7.65 W/mm at 18 GHz

Mark D. Hampson, Shyh Chiang Shen, Randal S. Schwindt, R. Kirk Price, Uttiya Chowdhury, Michael M. Wong, Ting Gang Zhu, Dongwon Yoo, Russell D. Dupuis, Milton Feng

Research output: Contribution to journalLetterpeer-review


Current metal-organic chemical vapor deposition-grown AlGaN-GaN heterojunction field-effect transistor devices suffer from threading dislocations and surface states that form traps, degrading RF performance. A passivation scheme utilizing a polyimide film as the passivating layer was developed to reduce the number of surface states and minimize RF dispersion. Continuous-wave power measurements were taken at 18 GHz on two-finger 0.23-μm devices with 2 × 75 μm total gate width before and after passivation yielding an increase from 2.14 W/mm to 4.02 W/mm in power density, and 12.5% to 24.47% in power added efficiency. Additionally, a 2 × 25 μm device yielded a peak power density of 7.65 W/mm at 18 GHz. This data suggests that polyimide can be an effective passivation film for reducing surface states.

Original languageEnglish (US)
Pages (from-to)238-240
Number of pages3
JournalIEEE Electron Device Letters
Issue number5
StatePublished - May 2004


  • Delta doping
  • Gallium nitride
  • Heterojunction field-effect transistor (HFET)
  • High-electron mobility transistor (HEMT)
  • Polyimide

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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