Scaling properties of growing surfaces of microcrystalline silicon

Growth-induced roughening of microcrystalline Si (μc-Si) surfaces has been studied from the viewpoint of self-similar and fractal structures in conjunction with crystallographic preferential orientations of μc-Si films. Typically, μc-Si films are prepared by plasma enhanced chemical vapor deposition (PECVD) with various preparation conditions including excitation frequency. Irrespective of preparation conditions, self-similarity of the μc-Si surface roughness derived by an atomic force microscope is well characterized in terms of its scaling exponents. Furthermore, the scaling exponents revealed that growth-induced roughness shows different behaviors in accordance with the crystallographic preferential orientations of the μc-Si films. Experimental results of scaling exponents are discussed regarding the origins of surface roughening in comparison to analytical results and numerical simulation results.