激光波长对非晶硅薄膜晶化效果的影响

Influence of wavelength on the crystallization of amorphous silicon thin film with CW lasers

为研究波长对连续激光晶化非晶硅(a-Si)薄膜过程的影响,利用连续Ar+-Kr+激光对a-Si薄膜晶化,在5ms固定照射时间下,改变激光波长,采用拉曼光谱测试技术和场发射扫描电子显微镜(SEM)研究在不同激光功率密度下薄膜晶化后的特性。结果表明,a-Si薄膜的晶化阈值随着波长的增大而增大,当波长为458nm时薄膜晶化阈值为13.2kW/cm2,波长为647nm时,晶化阈值为19.2kW/cm2;在激光功率密度范围为0~27.1kW/cm2内,薄膜的最大晶化率受波长的影响相对较小,但总体也随着波长的增大而呈增大趋势,当波长为647nm时,在激光功率密度26.5kW/cm2处,晶化率达到最大值75.85%。

For researching the irrfl^ence of laser wavelength on crystallization effect in continuous laser crystallization of amorphous silicOn （a-Si） thin film, the amorphous silicon thin film is crystallized by continuous Ar＋ --Kr＋ laser,under fixed irradiation time of 5 ms and different laser wavelengths. The film properties after crystallization iare studied by micro-Raman spectroscopic measurement and field e- mission scanning electron microscol^e. It is shown that the thin film crystallization threshold value gets larger with increase of wavelength,the crystallization threshold is 13.2 kW/cm2 when the wavelength is 458 nm and the crystallization threshold is 19.2 kW/cm2 when wavelength is 647 nm;in the range from 0 to 27.1 kW/cm2 ,the wavelength has less influence on the maximum crystalline fraction,but the value of maximum crystalline fraction gets larger with the increase of wavelength on the whole. Under the wavelength 647 nm and laser power density of 26.5 kW/cm2, the maximum crystalline fraction of 75.85% is obtained.