Growth-front roughening in amorphous silicon films by sputtering - art. no. 085323

The growth-front roughness of amorphous silicon films grown by de magnetron Sputtering at low pressure has been investigated, using atomic force micro scopy. The interface width tv increases as a power law of deposition time t , w similar tot(beta), with beta =0.41 +/- 0.01, and the lateral correlatio n length xi grows as xi similar tot(1/z) with 1/z =0.42 +/- 0.02. The rough ness exponent extracted from height-height correlation analysis is alpha =0 .83+/-0.03. None of the known growth models can be used to explain the scal ing exponents we obtained. Monte Carlo simulations were carried out based o n a re-emission model where incident flux distribution, sticking coefficien t, and surface diffusion were accounted for in the growth process. The morp hology and the scaling exponents obtained from simulations are consistent w ith the experimental results. When the surface diffusion is switched off in the simulation, columnar structures begin to appear and this is also consi stent with the experimental observations of other authors