激光脉冲频率对不同衬底上非晶硅薄膜晶化的影响

Influence of Laser Frequency on Crystallization of Amorphous Silicon Thin Films on Different Substrates

摘要:

应用不同频率的YAG激光分别对单晶硅及多晶硅衬底上的非晶硅薄膜进行了退火处理。晶化后的非晶硅薄膜的物相结构和表面形貌用XRD和AFM进行分析。XRD测试结果表明: 随着激光频率的增加, 两种衬底上的非晶硅薄膜晶化晶粒尺寸均出现了先增加后降低的现象。所有非晶硅样品的衍射峰位与衬底一致, 说明非晶硅薄膜的晶粒生长是外延生长。从多晶硅衬底样品的XRD可以看出, 随着激光频率的增加, 激光首先融化衬底表面, 然后衬底表层与非晶硅薄膜一起晶化。非晶硅薄膜最佳晶化激光频率分别为: 多晶硅衬底20Hz,单晶硅衬底10Hz。

Abstract:

The amorphous silicon thin films on crystal and poly silicon substrate were annealed by YAG laser with different frequencies. The analysis of microstructure and surface morphology was conducted using XRD and AFM. The XRD results show that the grain size of the crystallized amorphous films first increases then decreases with the laser frequency increasing. All the diffraction peaks of the samples are consistent with the peaks of the substrates, which means the grain growth in the films is the epitaxial growth. The XRD of poly substrate samples shows that the laser melts the surface of the substrate and then the poly surface crystallizes with the thin films with the increasing of the laser frequencies. The best crystallization laser frequencies for amorphous silicon thin films are on poly 20Hz and on crystal 10Hz.