自对准的光诱导化学镀/电镀技术以其栅线宽度小、工艺快捷高效等优点,成为制备选择性发射极太阳能电池的理想选择.然而,该技术的前序需要HF溶液有效去除重掺杂区表面SiO2的同时,避免在SiNx:H掩模上刻蚀出微孔而露出衬底的硅,否则金属镍和银会在光诱导化学镀/电镀工艺中沉积在微孔中,导致过镀现象.这就要求预处理溶液对SiO2/SiNx:H有很高的选择性刻蚀.本工作根据实验结果分析了产生过镀现象的原因,研究了进行SiO2/SiNx:H选择性刻蚀的可行性.依据HF刻蚀SiO2和SiNx:H的机理,通过调节HF缓释溶液的pH值,改善了多晶硅太阳能电池的过镀现象.
Self-aligned light-induced electroless plating/electro-plating technology, with its advantages of fine grid lines and fast and efficient process, became an ideal option for the preparation of selective emitter solar cells. However, before these technologies processing, the heavy doping area should be etched by HF solution to remove the surface SiO2 effectively and the pinholes should not emerge to expose the silicon substrate in the SiNx:H mask. Otherwise, the metal nickel and silver would deposit in the pinholes during the light-induced electroless plating/electro-plating resulting in the over-plating phenomenon. This demanded that the pretreatrnent solution should have highly selective etching for SiO2/SiNx:H. This paper analyzed the causes of the over-plating phenomenon in terms of the experiment results and studied the feasibility of selective etching for SiO2/SiNx:H. According to the mechanism of HF etching SiO2 and SiNx:H, the over-plating phenomenon of multicrystalline silicon solar cells was improved by adjusting the pH value of the buffer HF solution.