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Title: Characterization of interface states in Al{sub 2}O{sub 3}/AlGaN/GaN structures for improved performance of high-electron-mobility transistors

We have investigated the relationship between improved electrical properties of Al{sub 2}O{sub 3}/AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) and electronic state densities at the Al{sub 2}O{sub 3}/AlGaN interface evaluated from the same structures as the MOS-HEMTs. To evaluate Al{sub 2}O{sub 3}/AlGaN interface state densities of the MOS-HEMTs, two types of capacitance-voltage (C-V) measurement techniques were employed: the photo-assisted C-V measurement for the near-midgap states and the frequency dependent C-V characteristics for the states near the conduction-band edge. To reduce the interface states, an N{sub 2}O-radical treatment was applied to the AlGaN surface just prior to the deposition of the Al{sub 2}O{sub 3} insulator. As compared to the sample without the treatment, the N{sub 2}O-radical treated Al{sub 2}O{sub 3}/AlGaN/GaN structure showed smaller frequency dispersion of the C-V curves in the positive gate bias range. The state densities at the Al{sub 2}O{sub 3}/AlGaN interface were estimated to be 1 × 10{sup 12} cm{sup −2} eV{sup −1} or less around the midgap and 8 × 10{sup 12} cm{sup −2} eV{sup −1} near the conduction-band edge. In addition, we observed higher maximum drain current at the positive gate bias and suppressed threshold voltage instability under the negative gate bias stress even at 150 °C. Results presented in this paper indicated that the N{sub 2}O-radicalmore » treatment is effective both in reducing the interface states and improving the electrical properties of the Al{sub 2}O{sub 3}/AlGaN/GaN MOS-HEMTs.« less
Authors:
;  [1] ;  [1] ;  [2]
  1. Research Center for Integrated Quantum Electronics (RCIQE) and Graduate School of Information Science and Technology, Hokkaido University, North 13 West 8, Sapporo, 060-8628 Hokkaido (Japan)
  2. (JST), CREST, Tokyo 102-0075 (Japan)
Publication Date:
OSTI Identifier:
22267792
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 24; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM OXIDES; CAPACITANCE; ELECTRIC POTENTIAL; ELECTRON MOBILITY; FREQUENCY DEPENDENCE; GALLIUM NITRIDES; METALS; NITROUS OXIDE; PERFORMANCE; SEMICONDUCTOR MATERIALS; SILICON OXIDES; TRANSISTORS