We studied the kinetics of Ni-induced crystallization of amorphous silicon (a-Si) using a silicon-nitride (SiNx) cap layer (metal induced crystallization through a cap, MICC). Ni particles were sputtered onto the SiNx/a-Si layer, and then it was annealed in a rapid thermal annealing system. The Ni diffuses through a SiNx cap and then forms NiSi2 crystallites in a-Si, which is able to induce crystallization. The grain size increases from 27 to 50 mum with increasing the cap layer thickness from 50 to 350 nm and decreases from 80 to 27 mum with increasing the metal density on the cap from 1 x 10(14) to 5.5 x 10(14) atom/cm(2). These results can be interpreted by assuming a critical size of NiSi2 crystallite required to induce crystallization. The formation of NiSi2 crystallites, lateral crystallization from these seeds, and formation of disk-like grains have been observed by optical microscopy. (C) 2004 The Electrochemical Society.