准分子激光引起的非晶硅薄膜晶化行为的研究

Crystallization behavior of amorphous silicon thin films induced by excimer laser irradiation

利用KrF准分子激光对非晶硅薄膜的表层进行了晶化。研究了激光能量密度和照射脉冲数对薄膜结晶度的影响,并对晶化后薄膜的形貌和结构进行了表征。结果表明:该非晶硅薄膜晶化阈值约为110mJ/cm2,且不受照射脉冲数的影响;激光能量密度是影响薄膜结晶度的首要因素,但在较低的能量密度时,增加照射脉冲数也会显著的提高薄膜结晶度;结构及形貌表征发现,薄膜晶化层厚度约为400～500nm,平均晶粒尺寸为30～50nm。

KrF excimer laser was applied to the crystallization of the surface layer of amorphous silicon （a-Si） thin films. The influences of laser fluence and frequency of irradiation on the film crystallinity were investigated and the structure and morphology after crystallization were characterized. The results indicated that the laser crystallization threshold of the as-deposit a-Si films is near 110mJ/cm^2 and independent of the frequency of irradiation. The laser fluence is the predominant influencing foctor on film crystallinity, though increasing the frequency of irradiation can also improve the crystallinity efficiently when laser fluence is low. It was found that the fihn affer crystallization is of μc-Si/a-Si double-layer structure, of which the crystallized layer is 400-500nm thick with mean crystal grain size 30-50nm.