中国物理B ›› 2013, Vol. 22 ›› Issue (2): 27701-027701.doi: 10.1088/1674-1056/22/2/027701

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Effects of O2/Ar ratio and annealing temperature on electrical properties of Ta2O5 film prepared by magnetron sputtering

黄仕华, 程佩红, 陈勇跃   

  1. Department of Physics, Zhejiang Normal University, Jinhua 321004, China
  • 收稿日期:2012-07-12 修回日期:2012-08-05 出版日期:2013-01-01 发布日期:2013-01-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 61076055); the Program for Innovative Research Teams in Zhejiang Normal University, and the Open Project Program of Surface Physics Laboratory (National Key Laboratory) of Fudan University (Grant No. FDS KL2011_04).

Effects of O2/Ar ratio and annealing temperature on electrical properties of Ta2O5 film prepared by magnetron sputtering

Huang Shi-Hua (黄仕华), Cheng Pei-Hong (程佩红), Chen Yong-Yue (陈勇跃)   

  1. Department of Physics, Zhejiang Normal University, Jinhua 321004, China
  • Received:2012-07-12 Revised:2012-08-05 Online:2013-01-01 Published:2013-01-01
  • Contact: Huang Shi-Hua E-mail:huangshihua@zjnu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 61076055); the Program for Innovative Research Teams in Zhejiang Normal University, and the Open Project Program of Surface Physics Laboratory (National Key Laboratory) of Fudan University (Grant No. FDS KL2011_04).

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摘要： The effects of the oxygen-argon ratio on electric properties of Ta2O5 film prepared by radio-frequency magnetron sputtering were investigated. The Ta2O5 partially transforms from amorphous phase into crystal phase when annealing temperatures are 800℃ or higher. The lattice constant of Ta2O5 decreases with the increase of the O2/Ar ratio, which indicates that oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies during the deposition process. For the films deposited in working gas mixtures with different O2/Ar ratios and subsequently annealed at 700℃, the effective dielectric constant is increased from 14.7 to 18.4 with the increase of the O2/Ar ratio from 0 to 1. Considering the presence of an SiO2 layer between the film and the silicon substrate, the optimal dielectric constant of Ta2O5 film was estimated to be 31. Oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies, and the oxygen vacancy density and leakage current of Ta2O5 film both decrease with the increase of the O2/Ar ratio. The leakage current decreases after annealing treatment and it is minimized at 700℃. However, when the annealing temperature is 800℃ or higher, it increases slightly, which results from the partially crystallized Ta2O5 layer containing defects such as grain boundaries and vacancies.

关键词: Ta2O5 film, magnetron sputtering, C-V, oxide charge

Abstract: The effects of the oxygen-argon ratio on electric properties of Ta2O5 film prepared by radio-frequency magnetron sputtering were investigated. The Ta2O5 partially transforms from amorphous phase into crystal phase when annealing temperatures are 800℃ or higher. The lattice constant of Ta2O5 decreases with the increase of the O2/Ar ratio, which indicates that oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies during the deposition process. For the films deposited in working gas mixtures with different O2/Ar ratios and subsequently annealed at 700℃, the effective dielectric constant is increased from 14.7 to 18.4 with the increase of the O2/Ar ratio from 0 to 1. Considering the presence of an SiO2 layer between the film and the silicon substrate, the optimal dielectric constant of Ta2O5 film was estimated to be 31. Oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies, and the oxygen vacancy density and leakage current of Ta2O5 film both decrease with the increase of the O2/Ar ratio. The leakage current decreases after annealing treatment and it is minimized at 700℃. However, when the annealing temperature is 800℃ or higher, it increases slightly, which results from the partially crystallized Ta2O5 layer containing defects such as grain boundaries and vacancies.

Key words: Ta2O5 film, magnetron sputtering, C-V, oxide charge

中图分类号: 

  • 77.55.+f
84.37.+q (Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.))