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Title: Investigation on the electrical properties and inhomogeneous distribution of ZnO:Al thin films prepared by dc magnetron sputtering at low deposition temperature

Abstract

A study of the electrical properties and spatial distribution of the ZnO:Al (AZO) thin films prepared by dc magnetron sputtering at low deposition temperature was presented, with emphasis on the origin of the resistivity inhomogeneity across the substrate. Various growth conditions were obtained by manipulating the growth temperature T{sub S}, total pressure P{sub T}, and ion-to-neutral ratio J{sub i}/J{sub n}. The plasma characteristics such as radial ion density and floating/plasma potential distribution over the substrate were measured by Langmuir probe, while the flux and energy distribution of energetic species were estimated through Monte Carlo simulations. The crystalline, stress and electrical properties of the films were found to be strongly dependent on T{sub S} and J{sub i}/J{sub n}. Under the low J{sub i}/J{sub n} (<0.3) conditions, the T{sub S} exerted a remarkable influence on film quality. The films prepared at 90 deg. C were highly compressed, exhibiting poor electrical properties and significant spatial distribution. High quality films with low stress and resistivity were produced at higher T{sub S} (200 deg. C). Similarly, at lower T{sub S} (90 deg. C), higher J{sub i}/J{sub n} ({approx}2) dramatically improved the film resistivity as well as its lateral distribution. Moreover, it indicated that the rolemore » of ion bombardment is dependent on the mechanism of dissipation of incident species. Ion bombardment is beneficial to the film growth if the energy of incident species E{sub i} is below the penetration threshold E{sub pet} ({approx}33 eV for ZnO); on the other hand, the energy subimplant mechanism would work, and the bombardment degrades the film quality when E{sub i} is over the E{sub pet}. The energetic bombardment of negative oxygen ions rather than the positives dominated the resistivity distribution of AZO films, while the nonuniform distribution of active oxygen played a secondary role which was otherwise more notable under conditions of lower T{sub S} and J{sub i}/J{sub n}.« less

Authors:
; ; ;  [1]
  1. Division of Surface Engineering of Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)
Publication Date:
OSTI Identifier:
20884979
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 1; Other Information: DOI: 10.1063/1.2407265; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM; COMPUTERIZED SIMULATION; CRYSTAL GROWTH; ELECTRIC CONDUCTIVITY; ENERGY SPECTRA; ION BEAMS; ION DENSITY; LANGMUIR PROBE; MONTE CARLO METHOD; OXYGEN; OXYGEN IONS; PLASMA POTENTIAL; SEMICONDUCTOR MATERIALS; SPATIAL DISTRIBUTION; SPUTTERING; STRESS ANALYSIS; SUBSTRATES; SURFACE COATING; THIN FILMS; ZINC OXIDES

Citation Formats

Zhang, X. B., Pei, Z. L., Gong, J., and Sun, C. Investigation on the electrical properties and inhomogeneous distribution of ZnO:Al thin films prepared by dc magnetron sputtering at low deposition temperature. United States: N. p., 2007. Web. doi:10.1063/1.2407265.
Zhang, X. B., Pei, Z. L., Gong, J., & Sun, C. Investigation on the electrical properties and inhomogeneous distribution of ZnO:Al thin films prepared by dc magnetron sputtering at low deposition temperature. United States. doi:10.1063/1.2407265.
Zhang, X. B., Pei, Z. L., Gong, J., and Sun, C. Mon . "Investigation on the electrical properties and inhomogeneous distribution of ZnO:Al thin films prepared by dc magnetron sputtering at low deposition temperature". United States. doi:10.1063/1.2407265.
@article{osti_20884979,
title = {Investigation on the electrical properties and inhomogeneous distribution of ZnO:Al thin films prepared by dc magnetron sputtering at low deposition temperature},
author = {Zhang, X. B. and Pei, Z. L. and Gong, J. and Sun, C.},
abstractNote = {A study of the electrical properties and spatial distribution of the ZnO:Al (AZO) thin films prepared by dc magnetron sputtering at low deposition temperature was presented, with emphasis on the origin of the resistivity inhomogeneity across the substrate. Various growth conditions were obtained by manipulating the growth temperature T{sub S}, total pressure P{sub T}, and ion-to-neutral ratio J{sub i}/J{sub n}. The plasma characteristics such as radial ion density and floating/plasma potential distribution over the substrate were measured by Langmuir probe, while the flux and energy distribution of energetic species were estimated through Monte Carlo simulations. The crystalline, stress and electrical properties of the films were found to be strongly dependent on T{sub S} and J{sub i}/J{sub n}. Under the low J{sub i}/J{sub n} (<0.3) conditions, the T{sub S} exerted a remarkable influence on film quality. The films prepared at 90 deg. C were highly compressed, exhibiting poor electrical properties and significant spatial distribution. High quality films with low stress and resistivity were produced at higher T{sub S} (200 deg. C). Similarly, at lower T{sub S} (90 deg. C), higher J{sub i}/J{sub n} ({approx}2) dramatically improved the film resistivity as well as its lateral distribution. Moreover, it indicated that the role of ion bombardment is dependent on the mechanism of dissipation of incident species. Ion bombardment is beneficial to the film growth if the energy of incident species E{sub i} is below the penetration threshold E{sub pet} ({approx}33 eV for ZnO); on the other hand, the energy subimplant mechanism would work, and the bombardment degrades the film quality when E{sub i} is over the E{sub pet}. The energetic bombardment of negative oxygen ions rather than the positives dominated the resistivity distribution of AZO films, while the nonuniform distribution of active oxygen played a secondary role which was otherwise more notable under conditions of lower T{sub S} and J{sub i}/J{sub n}.},
doi = {10.1063/1.2407265},
journal = {Journal of Applied Physics},
number = 1,
volume = 101,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}