The solid phase crystallization behaviors of amorphous silicon thin films by adsorbing metal on the films was investigated. The amorphous silicon thin films were deposited by plasma enhanced chemical vapor deposition, spin-coated by metal solutions and subsequently annealed in Ar atmosphere.
The amorphous silicon thin films adsorbed from 1000 ppm of Al and Ni solutions by spin-coating were almost completely crystallized after 60 hours at 560℃ The metal solutions enhanced crystallization of amorphous silicon thin films. The metal induced crystallization of amorphous silicon thin films using metal adsorption method lowered the annealing temperature and reduced the annealing time for complete crystallization. The grain size of the crystallized Al-adsorbed silicon films was about 1.32㎛ and that of the crystallized Ni-adsorbed silicon films was about 1.01 ㎛. These grain size was half of that of crystallized intrinsic amorpous silicon films, while the crystallization time is much shorter.
The nucleation and growth behavior of the metal-adsorbed a-Si films was easily controlled by changing the solution concentration. The crystallization enhancement was generally promoted by increasing metal concentration in solution.
The crystallization temperature of the amorphous silicon films adsorbed from Al and Ni solutions at the same time was lower than that of the amorphous silicon films adsorbed from Al and Ni solutions separately. This is due to lower ternary eutectic temperature than binary eutectic temperature.
When the Al-adsorbed silicon films were annealed with Cu diffusion effect for 20 hours, the crystallization temperature lowered much and was 530℃. The crystallization temperature of the Al-adsorbed silicon films with Cu diffusion effect was 70℃ lower than that of the Al-adsorbed silicon films without diffusion effect and 90℃ lower than that of the intrinsic amorphous silicon films.