Dopant effect on in situ doped metal-induced lateral crystallization of amorphous silicon films

Dopant (boron or phosphorus) effect on metal-induced lateral crystallization (MILC) of amorphous silicon (a-Si) films has been systematically studied by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The MILC was realized by depositing a-Si film onto an oxidized Si wafer and then annealing in a N2 atmosphere. The doped amorphous films have been developed by plasma-enhanced chemical vapor deposition (PECVD). Various dopant gases and annealing times were investigated to study dopant effects on MILC films. It has been found that the un-doped poly-Si film has a MILC length larger than that of samples doped with boron or phosphorus. The phosphorus-doped films exhibit larger grain size as compared with un-doped and boron-doped films. Larger MILC length is obtained by increasing annealing time, but the MILC rate is decreased. In addition, nickel-silicides were found in the doped samples by XRD. Physical mechanisms for these experimental results are proposed.