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Title: Influence of Al{sub 2}O{sub 3} layer insertion on the electrical properties of Ga-In-Zn-O thin-film transistors

To investigate the influence of ionic/covalent interface of Al{sub 2}O{sub 3}/SiO{sub 2} gate insulator on the electrical properties of thin-film transistors (TFTs) with ionic Ga-In-Zn-O (GIZO) semiconducting channel layers, Al{sub 2}O{sub 3} layers of different thickness were introduced between SiO{sub 2} and GIZO using plasma-enhanced atomic layer deposition. The GIZO layers were obtained by DC magnetron sputtering using a GIZO target (Ga:In:Zn = 1:1:1 mol. %). The GIZO TFTs with an Al{sub 2}O{sub 3}/SiO{sub 2} gate insulator exhibited positive threshold voltage (V{sub th}) shift (about 1.1 V), V{sub th} hysteresis suppression (0.23 V), and electron mobility degradation (about 13%) compared with those of a GIZO TFT with SiO{sub 2} gate insulator by the influence of ionic/ionic and ionic/covalent interface at Al{sub 2}O{sub 3}/GIZO and Al{sub 2}O{sub 3}/SiO{sub 2}, respectively. To clarify the origin of the positive V{sub th} shift, the authors estimated the shifts of flatband voltage (0.4 V) due to the dipole and the fixed charge (−1.1 × 10{sup 11}/cm{sup 2}) at Al{sub 2}O{sub 3}/SiO{sub 2} interface, from capacitance–voltage data for Pt/Al{sub 2}O{sub 3}/SiO{sub 2}/p-Si capacitors. Based on these experimental data, the authors found that the positive V{sub th} shift (1.1 V) could be divided into three components: the dipole (−0.4 V) andmore » fixed charge (0.15 V) at the SiO{sub 2}/Al{sub 2}O{sub 3} interface, and the fixed charge (1.35 V) at the Al{sub 2}O{sub 3}/GIZO interface. Finally, it is noted that heterointerface of SiO{sub 2}/Al{sub 2}O{sub 3}/GIZO stacks is important not only to recognize mechanism of V{sub th} shift but also to design future TFTs with high-k dielectrics and low operating voltage.« less
Authors:
 [1] ;  [2] ; ; ; ; ;  [3] ;  [4] ;  [5] ;  [6]
  1. Department of Electronics and Bioinformatics, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan and Nano-Electronics Materials Unit, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)
  2. MANA Foundry and Nano-Electronics Materials Unit, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)
  3. International Center for Materials Nanoarchitectonics (WPA-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)
  4. MANA Foundry, International Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)
  5. Nano-Electronics Materials Unit, International Center for Materials Nanoarchitectonics (WPA-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)
  6. Department of Electronics and Bioinformatics, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan)
Publication Date:
OSTI Identifier:
22479673
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 33; Journal Issue: 6; Other Information: (c) 2015 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 42 ENGINEERING; ALUMINIUM OXIDES; CAPACITANCE; CAPACITORS; COVALENCE; DESIGN; DIELECTRIC MATERIALS; DIPOLES; ELECTRIC POTENTIAL; ELECTRON MOBILITY; HYSTERESIS; INTERFACES; LAYERS; MAGNETRONS; PLASMA; SILICA; SILICON OXIDES; SPUTTERING; THIN FILMS; TRANSISTORS