Modulation-doped superlattice AlGaN barrier GaN/AlGaN HFETs

Uttiya Chowdhury, Raymond K. Price, Michael M. Wong, Dongwon Yoo, Xuebing Zhang, Milton Feng, Russell D. Dupuis

Research output: Contribution to journalArticlepeer-review


For nitride heterojunction field-effect transistors, the heterojunction forming the electron barrier has to be designed based on trade-offs between lattice mismatch, two-dimensional electron gas concentration, and alloy scattering. In this work, we study the use of a superlattice-based barrier which effectively increases the heterojunction barrier while reducing the lattice mismatch and alloy scattering. The structure studied consists of a five-period superlattice of 2 nm Al0.2Ga0.8N + 2 nm Al 0.3Ga0.7N on GaN grown using metalorganic chemical vapor deposition on a 6 H SiC conducting substrate. The barriers of the second and third period of the superlattice are Si-doped to give the effect of modulation doping. Devices fabricated from the structure exhibit a high gm of ∼299 mS/mm and an Ids max of 0.85 A/mm. To our knowledge, this is the first investigation of the use of superlattice structure for improvement of the barrier properties in a nitride HFET.

Original languageEnglish (US)
Pages (from-to)318-321
Number of pages4
JournalJournal of Crystal Growth
Issue number1-4 SPEC. ISS.
StatePublished - Dec 10 2004


  • A1. Doping
  • A3. Low pressure metalorganic vapor phase epitaxy
  • B1. Nitrides
  • B2. Semiconducting III-V materials
  • B3. Heterojunction semiconductor devices

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry


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