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Title: Effect of postdeposition annealing on the electrical properties of β-Ga{sub 2}O{sub 3} thin films grown on p-Si by plasma-enhanced atomic layer deposition

Ga{sub 2}O{sub 3} dielectric thin films were deposited on (111)-oriented p-type silicon wafers by plasma-enhanced atomic layer deposition using trimethylgallium and oxygen plasma. Structural analysis of the Ga{sub 2}O{sub 3} thin films was carried out using grazing-incidence x-ray diffraction. As-deposited films were amorphous. Upon postdeposition annealing at 700, 800, and 900 °C for 30 min under N{sub 2} ambient, films crystallized into β-form monoclinic structure. Electrical properties of the β-Ga{sub 2}O{sub 3} thin films were then investigated by fabricating and characterizing Al/β-Ga{sub 2}O{sub 3}/p-Si metal–oxide-semiconductor capacitors. The effect of postdeposition annealing on the leakage current densities, leakage current conduction mechanisms, dielectric constants, flat-band voltages, reverse breakdown voltages, threshold voltages, and effective oxide charges of the capacitors were presented. The effective oxide charges (Q{sub eff}) were calculated from the capacitance–voltage (C-V) curves using the flat-band voltage shift and were found as 2.6 × 10{sup 12}, 1.9 × 10{sup 12}, and 2.5 × 10{sup 12} cm{sup −2} for samples annealed at 700, 800, and 900 °C, respectively. Effective dielectric constants of the films decreased with increasing annealing temperature. This situation was attributed to the formation of an interfacial SiO{sub 2} layer during annealing process. Leakage mechanisms in the regions where current increases gradually with voltage were well fitted by the Schottkymore » emission model for films annealed at 700 and 900 °C, and by the Frenkel–Poole emission model for film annealed at 800 °C. Leakage current density was found to improve with annealing temperature. β-Ga{sub 2}O{sub 3} thin film annealed at 800 °C exhibited the highest reverse breakdown field value.« less
Authors:
 [1] ; ; ;  [2]
  1. Faculty of Science, Department of Physics, Cankiri Karatekin University, Cankiri 18100 (Turkey)
  2. National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey and Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey)
Publication Date:
OSTI Identifier:
22318072
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 32; Journal Issue: 4; Other Information: (c) 2014 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DIELECTRIC MATERIALS; ELECTRIC POTENTIAL; GALLIUM OXIDES; LEAKAGE CURRENT; MONOCLINIC LATTICES; OXYGEN; SEMICONDUCTOR MATERIALS; SILICON OXIDES; THIN FILMS; X-RAY DIFFRACTION