Graded AlGaN Channel Transistors for Improved Current and Power Gain Linearity

Bajaj S., Yang Z., Akyol F., PARK P. S., Zhang Y., Price A. L., ...More

IEEE TRANSACTIONS ON ELECTRON DEVICES, vol.64, no.8, pp.3114-3119, 2017 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 64 Issue: 8
  • Publication Date: 2017
  • Doi Number: 10.1109/ted.2017.2713784
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.3114-3119
  • Keywords: Graded AlGaN, constant f(T), gain linearity, GaN, graded AlGaN, high-electron-mobility transistor (HEMT), polarization-doped field-effect transistor (PolFET), ELECTRON-MOBILITY TRANSISTORS, MOLECULAR-BEAM EPITAXY, OHMIC CONTACTS, HEMTS, F(T)
  • Yıldız Technical University Affiliated: No


We report on the small-signal high frequency characteristics of highly scaled graded AlGaN channel polarization-doped field-effect transistors (PolFETs) that show constant current gain cutoff frequency (f(T)) and maximum oscillation frequency (f(max)) profiles as a function of current density or gate bias. The device design includes upward and downward Al composition grading to induce a distributed 3-D charge profile, and eliminate abrupt heterojunction band offsets to achieve nonalloyedohmic contacts with low resistance. The highest extrinsic f(T) of 52 GHz and fmax of 67 GHz weremeasured at V-GS = -1.5 V andVDS = 9 V, and constant fT and fmax over wide input voltage (VGS) and output current range (IDS) were achieved.