氩气分压与膜厚对溅射Al膜微结构及应力的影响

在不同氩气分压下,用直流溅射法在室温Si基片上制备了不同厚度的Al膜。用光学干涉相移法和X射线衍射技术,对薄膜应力和微结构进行了测试分析。微结构分析表明:制备的Al膜均呈多晶状态,晶体结构仍为面心立方;氩气分压分别为1Pa和3Pa的Al膜相比,1Pa下制备的薄膜结晶程度明显优于3Pa下制备的薄膜。1Pa下Al膜平均晶粒尺寸随膜厚的增加由17.9nm逐渐增大到26.3nm;晶格常数由0.4037nm增大到0.4047nm,均比标准值0.40496nm稍小。应力分析表明:同一工作气体压强(氩气分压)下,Al膜的平均应力随着膜厚的增加变小,应力分布趋向均匀。相同时间1Pa和3Pa的Al膜,其微结构和应力有较大差别。

Effect of Ar pressure and film thickness on the microstructure and stress properties of Al films

Al films, grown on Si wafers by DC magnetron sputtering, were studied with X-ray diffraction and optical phase-shift technology at different Ar pressures. The results of microstructure analysis show that the Al films consist of face-centered cubic(FCC) Al grains. Comparing the Al films sputtered at different Ar pressures, it is found that the crystallization of the Al films whose Ar pressure is (1 Pa is) better than the others, and the mean grain size of the Al films whose Ar pressure is (1 Pa is) bigger than that of which pressure of Ar is 3 Pa. When the pressure of Ar is 1 Pa, the mean grain size of the Al film increases from 17.9 nm to 26.3nm, and the lattice constant of the Al film increases from 0.403 7 nm to 0.404 7 nm, with the thicknesses of the Al film increasing. The results of stress analysis show that at the same Ar pressure, the average stress of the Al films becomes smaller and the distribution of the stress becomes more uniform with the thickness of the Al film increasing. Comparing the Al films deposited at different Ar pressures and the same sputtering time, it is concluded that the stress status of the Al films grown at Ar pressure of 1 Pa is better than the others.