磁控溅射Cu膜表面形貌演化的多尺度行为

MULTI-SCALE SURFACE MORPHOLOGY EVOLUTION OF COPPER THIN FILMS DEPOSITED BY MAGNETRON SPUTTERING

用原子力显微镜(AFM)观察磁控溅射Cu膜的表面形貌,并基于功率谱密度(PSD)和粗糙度测量方法对薄膜进行了量化表征,研究了薄膜表面演化的动力学标度行为.结果表明:薄膜表面演化具有多尺度特征,在全域和局域呈现两种不同的标度行为.全域的粗糙度指数α_g≈0.83,生长指数β_g≈0.85;而局域的粗糙度指数α_1≈0.88,生长指数β_1≈0.26.这种差异揭示了薄膜生长机制的尺度依赖性.薄膜全域表面演化为异常标度行为,这归因于体扩散导致了晶粒几何形态的急剧变化;而局域表面演化呈现表面扩散控制的生长行为.

The surface morphologies of Cu thin films deposited by magnetron sputtering were obtained by atomic force microscopy （AFM）. From AFM images, the power spectrum density （PSD） and roughness measurement methods were used to obtain dynamic scaling exponents of the film surface evolution. The results show that the film surface evolution has multi-scale feature. The global roughness exponent αg and growth exponent βg are 0.83 and 0.85, respectively, whereas the local roughness exponent α1 and growth exponent β1 are 0.88 and 0.26, respectively. The local dynamic surface evolution is consistent with that predicted by surface diffusion-dominated growth model. The global surface dynamic evolution exhibits anomalous scaling characteristic, which arises from the change of grain geometry induced by bulk diffusion mechanism during the film growth at higher temperature.