用区熔技术改善多晶硅薄膜颗粒硅带衬底的质量

Quality Improvement of SSP as the Substrate of Polycrystalline Silicon Thin Film Via ZMR Technique

以颗粒硅带为衬底,通过化学气相沉积法制备多晶硅薄膜作为太阳电池的活性层.为了改善硅带衬底的质量,引入区熔再结晶的方法,期望将其表面平整度及结晶质量进一步提高,进而改善以其为衬底的多晶硅薄膜质量.借助台阶仪、X射线衍射(XRD)、扫描电镜(SEM)等手段对颗粒硅带及多晶硅薄膜进行了表面轮廓、结晶质量和微观形貌的表征.结果表明:区熔后的颗粒硅带表面平整度得到了较好的改善;表面具有[311]择优方向的硅带区熔后都倾向[111]择优;在区熔硅带衬底上沉积的多晶硅薄膜晶粒尺寸在100μm以上,但暂无明显证据证明区熔对薄膜结晶质量有显著提高.

The polycrystalline silicon (Poly-Si) thin film, an active layer of the solar cell, was prepared by means of Chemical Vapor Deposition (CVD) with SSP (Silicon Sheet from Powder) as the substrate. The ZMR (Zone Melting Recrystallization) technique was next introduced to improve the smoothness and crystal quality of SSP and to further improve the quality of the thin film. The surface profiles, micro-morphologies and crystal quality of SSP ribbon and Poly-Si film were then investigated by the step profiler, XRD (X-ray Diffraction) and SEM (Scanning Electron Microscopy). It is shown that the surface smoothness of SSP is improved after the ZMR process, and SSP with [311] preferred orientation tends to grow in [111] preferred orientation. Moreover, the crystal size of the thin film on SSP ribbon via ZMR is more than 100m, but there is not yet enough evidence to prove that ZMR greatly improves the crystal quality of Poly-Si thin film.