采用两步化学腐蚀法在多晶硅材料的表面制备了绒面结构,其中两步腐蚀法包括酸-碱两步腐蚀法和酸-酸两步腐蚀法。通过表面形貌SEM和反射谱的测试,详细地研究了不同腐蚀条件和腐蚀溶液制备绒面的形貌和光学特征。实验发现,当腐蚀速率较快时,多晶硅的绒面形貌会出现大量的晶界和针孔效应,并分析了其形成原因。同时,采用酸-碱两步腐蚀法的效果优于酸-酸两步腐蚀法的效果。最后,用PECVD在绒面上沉积SiNx减反射膜,使表面的反射率在600~800nm范围内降到3%左右,达到了良好的减反射效果,得出了最优的绒面制备方案。
Multi-crystalline silicon wafers were textured by double chemical treatments,which include acid-alkali and double acid treatments.By using SEM and reflectance spectrum,detailed study of surface morphology and optical properties of different etched surfaces was carried out.The results show that a large number of grain boundary delineation and pinholes will produce when the etching rate is too fast,and the reason is also discussed.And the results of acid-alkali treatment are better than that of double acid treatment.With PECVD AR coating of silicon nitride film,the reflectivity of texturing is reduced to be about 3% in the wavelength of 600~800 nm.Excellent preparation schemes are achieved.