中国激光, 2009, 36 (1): 205, 网络出版: 2009-02-10
平顶绿光晶化制备多晶硅薄膜
Flat-Top Green Laser Crystallization of Amorphous Silicon Thin Film
薄膜 多晶硅 激光晶化 倍频Nd∶YAG激光 平顶光束 thin film polycrystalline silicon laser crystallization frequency-doubled Nd∶YAG laser flattop beam
摘要
利用倍频Nd∶YAG激光器使玻璃基底上沉积的非晶硅薄膜成功实现了晶化。YAG激光器的倍频绿光经蝇眼透镜阵列整形后得到一光强均匀分布的平顶光束, 并用此光束对非晶硅薄膜进行扫描晶化处理。分别测量了激光晶化前后薄膜的拉曼谱和表面形貌。测量结果表明, 非晶硅实现了到多晶硅的相变, 且晶化处理后表面起伏度明显增大。根据拉曼谱的数据计算了不同激光能量密度下薄膜的粒度大小和结晶度。结果表明, 在一定能量密度(400~850 mJ/cm2)范围内, 结晶膜的晶粒粒度和结晶度随激光能量密度升高而增大。然而能量密度大于1000 mJ/cm2后, 检测不到明显的多晶硅特征峰。激光能量密度在850 mJ/cm2左右可得到最佳晶化效果。
Abstract
Amorphous silicon thin films deposited on glass are successfully crystallized by frequency-doubled Nd∶YAG laser with a flat-top beam. Beam shaping optical system of fly′s eye lens array for achieving flat-top beam with uniform intensity distribution is introduced, and with this beam the amorphous silicon thin films is crystallized. The surface morphology of laser-crystallized samples are studied by atomic force microscopy. Raman spectra are measured to confirm the phase transition from amorphous silicon to polycrystalline silicon (poly-Si), and the surface roughness of the thin film after crystallization is enhanced. The grain size and crystallinity are calculated for different laser fluences with Raman spectral data. Both of the grain size and crystallinity evaluated from the data of Raman spectra are found to increase almost linearly with the laser fluence from 400 to 850 mJ/cm2. However, the Raman signal for poly-Si disappeares when the laser fluence exceeds 1000 mJ/cm2. In this experiment, it is about 850 mJ/cm2 to produce the best crystallization.
袁志军, 楼祺洪, 周军, 董景星, 魏运荣, 王之江. 平顶绿光晶化制备多晶硅薄膜[J]. 中国激光, 2009, 36(1): 205. Yuan Zhijun, Lou Qihong, Zhou Jun, Dong Jingxing, Wei Yunrong, Wang Zhijiang. Flat-Top Green Laser Crystallization of Amorphous Silicon Thin Film[J]. Chinese Journal of Lasers, 2009, 36(1): 205.