ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
We report the results of ellipsometry measurements performed during the growth of hydrogenated amorphous silicon (a-Si:H) thin films on crystalline silicon substrates using ion beam sputtering. The data have been compared to our earlier results for high-quality a-Si:H prepared by glow-discharge decomposition of SiH4, and significant differences in the initial nucleation and microstructural evolution have been deduced for the two types of films. For the glow-discharge a-Si:H, the in situ pseudodielectric function data provided evidence for the convergence of initial growth microstructure in the first ∼50 A(ring), leaving a-Si:H of near bulk Si–Si bond-packing density at the interface to the c-Si substrate. After the nucleation process, growth was found to be nearly layer by layer. The data for the sputtered a-Si:H also reveal the formation of a low-density microstructure in the initial stages of growth. However, in contrast to the glow-discharge films, the microstructure does not converge, and an extensive layer (∼200–400 A(ring)) of bond-packing density lower than the bulk is left at the interface to the substrate. The effect of hydrogen incorporation on this and other aspects of the microstructural evolution of the sputtered films is discussed. Finally, similarities observed between the microstructural evolution of the sputtered films and poorer-quality glow-discharge films provide insights into the growth mechanisms.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.339132
