Crystallization and ablation in annealing of amorphous-Si thin film on glass and crystalline-Si substrates irradiated by third harmonics of Nd3+:YAG laser
Crystallization and ablation in annealing of amorphous-Si thin film on glass and crystalline-Si substrates irradiated by third harmonics of Nd3+:YAG laser
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DOI：
10.1016/j.mssp.2009.05.001
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发表时间：
2008-08-01
影响因子：
4.1
通讯作者：
Singaperumal, M.
中科院分区：
文献类型：
--
作者：
Palani, I. A.;Vasa, Nilesh J.;Singaperumal, M.
研究了利用Nd ~（3+）：YAG全固态脉冲激光（355 nm）的三次谐波将非晶硅（a-Si）薄膜转变为多晶薄膜的方法。在170 ~ 960 mj/cm ~ 2的激光能量密度范围内，对无碱玻璃衬底上的a-Si薄膜（a-Si/glass）和晶态Si衬底上的a-Si薄膜（a-Si/c-Si）进行了激光处理。通过求解一维热方程模型，对入射到表面的热量进行了理论分析。对烧蚀阈值、晶化区域和晶化深度进行了理论研究。通过原位反射率测量、扫描电子显微镜（SEM）和拉曼光谱研究，对激光辐照、烧蚀和结晶度的影响进行了实验分析。在a-Si/c-Si的情况下，结晶的程度和结构特性对电子性能的影响进行了研究，使用霍尔效应技术。烧蚀阈值和晶化区范围与理论计算结果吻合较好。要求激光能量密度在300和500 mJ/cm（2）之间。对于厚度达400 nm的a-Si薄膜，烧蚀阈值估计在500 mJ/cm（2）以上。(C)2009爱思唯尔有限公司版权所有。
In the present research, an approach of converting amorphous-silicon (a-Si) thin films into polycrystalline thin films using the third harmonics of an all-solid-state pulsed Nd3+:YAG laser (355 nm) is studied. Two different samples of a-Si thin films on alkalifree glass (a-Si/glass) substrates and a-Si thin film on crystalline-Si substrates (a-Si/c-Si) are laser treated at different laser fluences ranging from 170 to 960 mj/cm(2). The amount of heat incident on the surface has been analyzed theoretically by solving the one-dimensional heat-equation model. The ablation threshold, the region of crystallization and the depth of crystallization have been investigated theoretically. The influence of laser irradiation, ablation and crystallinity has been experimentally analyzed through in-situ reflectivity measurements, scanning electron microscopy (SEM) and Raman spectroscopy studies. In the case of a-Si/c-Si, the extent of crystallinity and the influence of structural characteristics on electronic properties are studied using the Hall-effect technique. The ablation threshold and the range of crystallization regime are in good agreement with the theoretical results. Laser fluence between 300 and 500 mJ/cm(2) is required. for crystallization and the ablation threshold is estimated to be above 500 mJ/cm(2) for a-Si thin film with a thickness up to 400 nm. (C) 2009 Elsevier Ltd. All rights reserved.