Studies On Preparing Poly-Si Thin Film On Ssp Substrate At Low-temperature

Poly Silicon Thin Film Solar Cell has the characteristic of high performance, low cost. As we know, the cheap base material is the key to ultimately realize the Cell coming into industrialization. We prepared poly-silicon thin films on the base named Ssp(Silicon Sheets from Powder) which is very cheap. On the course, we investigated the preparing technology at the same time. The experimental results show that the thin films deposited by PECVD method currently are still amorphous. If treated further by SPC(Solid Phase Crystallization), the pollution will be brought by impurity's diffusion. Hardly can we deposit poly silicon thin films with no purity on SSP substrate.In order to prepare the purified poly silicon thin film, we deposited a bed of nickel on the sample's face by Magnetron Sputtering method, then put the samples into anneal for some time and cleaned them with diluted muriatic acid. After depositing nickel and anneal the ultimate results show at least two fact, one fact is that the diffusion of the impurity of the SSP substrate is obviously restrained; the other is that the nickel has inducing effect for the thin film translating from amorphous state to crystal state. Finally we realized preparing high-purified poly silicon thin film at low temperature.From the experiment's result we can see the effect of the metal inducing crystallization is obvious, though there's no a perfect theory about MIC that can explain all kind of phenomena on the experiment yet. In this paper, we analyze the success and the limitation of the actual MIC's theory, and we put forward a mechanism model whose name is "The Diffusion Model of Metal Induced(Lateral) Crystallization". The formula deduced from this Model can successfully explain all kinds of experiment phenomena about metal induced crystallization by qualitative method as well as by quantitative method.This paper derives from the practical need; on this base we have explored and studied the technology on prepration of poly silicon thin film. We have successfully deposited the thin film and put forward a correlated theory model- The Diffusion Model of Metal Induced(Lateral) Crystallization, and the model can explain the experiment's result well.