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Title: Role of the (Ta/Nb)O{sub x}/Al{sub 2}O{sub 3} interface on the flatband voltage shift for Al{sub 2}O{sub 3}/(Ta/Nb)O{sub x}/Al{sub 2}O{sub 3} multilayer charge trap capacitors

The authors studied the characteristics of Si/Al{sub 2}O{sub 3}/(Ta/Nb)O{sub x}/Al{sub 2}O{sub 3}/SiO{sub 2}/Pt charge trap capacitors fabricated by atomic layer deposition and postmetallization annealing at 400 °C. Al{sub 2}O{sub 3} and (Ta/Nb)O{sub x} films are amorphous and have negligible fixed charges. In program mode, a flatband voltage (V{sub fb}) drastically shifts toward the positive direction at a short program time of 10{sup −4} s. A large V{sub fb} shift of approximately 4 V arises after programming at 1 mC/cm{sup 2} because there is a large difference in the conduction band offset between the (Ta/Nb)O{sub x}-charge trapping layer (TNO-CTL) and the Al{sub 2}O{sub 3}-blocking layer (AlO-BL) (1.8 eV). In the retention mode, most of the trapped electrons in the TNO-CTL transfers across the Al{sub 2}O{sub 3}-tunneling layer (AlO-TL) rather than the AlO-BL. The thickness of the AlO-TL affects the V{sub fb} shift degradation behavior in the retention mode. The injected electrons are dominantly located at the TNO-CTL/ALO-BL interface, determined from the thickness dependence of the TNO-CTL on the V{sub fb} shift.
Authors:
 [1] ;  [2] ; ;  [3] ;  [4]
  1. MANA Foundry and Nano-Electronics Materials Unit, International Center for Materials Nanoarchitectonics, National Institute for Materials Science (WPI-MANA), 1-1 Namiki, Tsukuba 305-0044, Japan and CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 322-0012 (Japan)
  2. MANA Foundry, International Center for Materials Nanoarchitectonics, National Institute for Materials Science (WPI-MANA), 1-1 Namiki, Tsukuba 305-0044 (Japan)
  3. Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)
  4. Nano-Electronics Materials Unit, International Center for Materials Nanoarchitectonics, National Institute for Materials Science (WPI-MANA), 1-1 Namiki, Tsukuba 305-0044 (Japan)
Publication Date:
OSTI Identifier:
22392093
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 33; Journal Issue: 1; Other Information: (c) 2014 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; ANNEALING; CAPACITORS; DEPLETION LAYER; ELECTRIC POTENTIAL; FILMS; INTERFACES; SILICA; SILICON OXIDES; THICKNESS; TRAPPED ELECTRONS; TRAPS; TUNNEL EFFECT