CRYSTAL GRAIN NUCLEATION IN AMORPHOUS-SILICON

The solid phase crystallization of chemical vapor deposited amorphous silicon films onto oxidized silicon wafers, induced either by thermal annealing or by ion beam irradiation at high substrate temperatures, h as been extensively developed and it is reviewed here. We report and d iscuss a large variety of processing conditions. The structural and th ermodynamical properties of the starting phase are emphasized. The mor phological evolution of the amorphous towards the polycrystalline phas e is investigated by transmission electron microscopy and it is interp reted in terms of a physical model containing few free parameters rela ted to the thermodynamical properties of amorphous silicon and to the kinetical mechanisms of crystal grain growth. A direct extension of th is model explains also the data concerning the ion-assisted crystal gr ain nucleation. (C) 1998 American Institute of Physics. [S0021-8979(98 )00122-4].