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Title: Insights into ultraviolet-induced electrical degradation of thermally grown SiO{sub 2}/4H-SiC(0001) interface

The harmful impact of ultraviolet (UV) light irradiation on thermally grown SiO{sub 2}/4H-SiC structures was investigated by means of electrical measurements of metal-oxide-semiconductor (MOS) capacitors. Unlike Si-based MOS devices, significant electrical degradation, such as positive flatband voltage (V{sub FB}) shift and hysteresis in the capacitance-voltage (C-V) curves of SiC-MOS capacitors was induced by UV irradiation with a low-pressure mercury lamp. The interfacial fixed charge density increased with UV-irradiation (22.6 mW/cm{sup 2} for 16 h) to 1.7 × 10{sup 12} cm{sup −2}, which was an order of magnitude larger than that of the as-grown SiO{sub 2}/SiC interface. A detailed study based on single wavelength solid-state UV lasers revealed that there was a threshold photon energy at around 5 eV and a moderate dependence of UV-induced degradation on temperature. These experimental findings imply that pre-existing inactive defects accumulated at the thermally grown SiO{sub 2}/SiC interface were transformed to active carrier traps with high-energy UV irradiation through transparent SiO{sub 2} layers.
Authors:
; ; ;  [1] ; ;  [2]
  1. Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)
  2. Power Electronics R and D Unit, ROHM CO., LTD., 21 Saiin Mizosaki-cho, Ukyo-ku, Kyoto 615-8585 (Japan)
Publication Date:
OSTI Identifier:
22257143
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 1; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CAPACITORS; HYDROGEN 4; MERCURY; SEMICONDUCTOR MATERIALS; SILICA; SILICON CARBIDES; SILICON OXIDES; ULTRAVIOLET RADIATION