本征非晶硅薄膜的准分子激光晶化

Crystallization of amorphous silicon based on excimer laser

为了减低非晶硅薄膜太阳能电池的光致衰减效应和提高其光电转换效率,用等离子体化学气相沉积系统制备了本征非晶硅薄膜,用波长为248nm的KrF准分子激光器激光晶化了非晶硅表层,用共焦显微喇曼测试技术研究了非晶硅薄膜在不同的激光能量密度和不同的频率下的晶化状态,并用扫描电子显微镜测试晶化前后薄膜的形貌。结果表明,随着激光能量密度的增大,薄膜晶化效果越来越好,能量密度达到268.54mJ/cm2时晶化效果最好,此时结晶比约为76.34%;最佳的激光能量密度范围是204.99mJ/cm2～268.54mJ/cm2,这时薄膜表面晶化良好;在1Hz～10Hz范围内,激光频率越大晶化效果越好;晶化后薄膜明显出现微晶和多晶颗粒,从而达到了良好的晶化效果。

In order to reduce the ＂S-W effect＂ of amorphous silicon thin film solar cells and increase its photoelectric conversion efficiency, intrinsic amorphous silicon thin films prepared by plasma enhanced chemical vapov deposition were crystallized with KrF excimer laser. The crystalline effect of the crystallized films under different laser energy density and repeated frequency was characterized with Raman spectroscopy, the morphologies of the samples before and after the crystallization was studied by means of scanning electron microscope. It is shown that the crystallization effect became better with the increase of laser energy density, maximum value of crystallization rate was 76. 34% when the energy density reached 268.54mJ/cm^2 and the optimum energy density range was from 204. 99mJ/cm^2 to 268.54mJ/cm^2 in which the surface of film was crystallized well. In the range of 1Hz -10Hz, the crystallization effect got better with the increase of laser repeation frequency. Microerystalline and polycrystal particles appeared obviously after the crystallization so that a good crystallization effect was achieved.