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