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Title: Investigation of defects in In–Ga–Zn oxide thin film using electron spin resonance signals

In–Ga–Zn oxide (IGZO) is a next-generation semiconductor material seen as an alternative to silicon. Despite the importance of the controllability of characteristics and the reliability of devices, defects in IGZO have not been fully understood. We investigated defects in IGZO thin films using electron spin resonance (ESR) spectroscopy. In as-sputtered IGZO thin films, we observed an ESR signal which had a g-value of g = 2.010, and the signal was found to disappear under thermal treatment. Annealing in a reductive atmosphere, such as N{sub 2} atmosphere, generated an ESR signal with g = 1.932 in IGZO thin films. The temperature dependence of the latter signal suggests that the signal is induced by delocalized unpaired electrons (i.e., conduction electrons). In fact, a comparison between the conductivity and ESR signal intensity revealed that the signal's intensity is related to the number of conduction electrons in the IGZO thin film. The signal's intensity did not increase with oxygen vacancy alone but also with increases in both oxygen vacancy and hydrogen concentration. In addition, first-principle calculation suggests that the conduction electrons in IGZO may be generated by defects that occur when hydrogen atoms are inserted into oxygen vacancies.
Authors:
; ; ; ; ; ; ; ;  [1] ; ; ;  [2] ;  [1] ;  [3]
  1. Semiconductor Energy Laboratory Co., Ltd., 398 Hase, Atsugi, Kanagawa 243-0036 (Japan)
  2. Advanced Film Device, Inc., 161-2 Masuzuka, Tsuga-machi, Tochigi, Tochigi 328-0114 (Japan)
  3. (Japan)
Publication Date:
OSTI Identifier:
22273507
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 16; 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; ABSORPTION SPECTROSCOPY; ANNEALING; CONCENTRATION RATIO; ELECTRON SPIN RESONANCE; ELECTRONS; G VALUE; GALLIUM COMPOUNDS; INDIUM COMPOUNDS; SEMICONDUCTOR MATERIALS; TEMPERATURE DEPENDENCE; THIN FILMS; VACANCIES; ZINC OXIDES