Lateral Size Evolution of Coalescent Grains on Microcrystalline Silicon Surface

Abstract

Growth-induced topographic surface evolutions of microcrystalline Si (µc-Si) have been studied from the fractal concept with emphasis on the lateral size of coalescent grains appearing on the surface. µc-Si films were deposited by plasma-enhanced chemical vapor deposition with different thicknesses of 0.5–4.3 µm. From the surface heights, the lateral correlation length ξ was estimated, and the lateral size of the grains is approximately expressed as 2ξ. Moreover, a power-law relationship is found between ξ and thickness with the scaling exponent 1/z', which reflects the crystallographic preferential orientation. Compared with the scaling exponent estimated from the roughness evolution, the difference between columnar and granular growths is characterized.