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Title: Role of the dielectric for the charging dynamics of the dielectric/barrier interface in AlGaN/GaN based metal-insulator-semiconductor structures under forward gate bias stress

The high density of defect states at the dielectric/III-N interface in GaN based metal-insulator-semiconductor structures causes tremendous threshold voltage drifts, ΔV{sub th}, under forward gate bias conditions. A comprehensive study on different dielectric materials, as well as varying dielectric thickness t{sub D} and barrier thickness t{sub B}, is performed using capacitance-voltage analysis. It is revealed that the density of trapped electrons, ΔN{sub it}, scales with the dielectric capacitance under spill-over conditions, i.e., the accumulation of a second electron channel at the dielectric/AlGaN barrier interface. Hence, the density of trapped electrons is defined by the charging of the dielectric capacitance. The scaling behavior of ΔN{sub it} is explained universally by the density of accumulated electrons at the dielectric/III-N interface under spill-over conditions. We conclude that the overall density of interface defects is higher than what can be electrically measured, due to limits set by dielectric breakdown. These findings have a significant impact on the correct interpretation of threshold voltage drift data and are of relevance for the development of normally off and normally on III-N/GaN high electron mobility transistors with gate insulation.
Authors:
 [1] ;  [2] ; ; ; ; ;  [1] ; ; ; ;  [3] ;  [4]
  1. Infineon Technologies Austria AG, Siemensstraße 2, 9500 Villach (Austria)
  2. (Austria)
  3. Fraunhofer IPMS-CNT, Königsbrücker Straße 178, 01099 Dresden (Germany)
  4. Institute of Solid State Electronics, Vienna University of Technology, Floragasse 7, 1040 Wien (Austria)
Publication Date:
OSTI Identifier:
22311357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 3; Other Information: (c) 2014 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 COMPOUNDS; BREAKDOWN; CAPACITANCE; CRYSTAL DEFECTS; DIELECTRIC MATERIALS; ELECTRIC POTENTIAL; ELECTRON MOBILITY; GALLIUM NITRIDES; INTERFACES; METALS; SCALING; SEMICONDUCTOR MATERIALS; THICKNESS; TRANSISTORS; TRAPPED ELECTRONS