基于BCl_(3)源的低压硼扩散设备及工艺研究

BCl_(3)-sourced Low Pressure Boron Diffusion Equipment and Process Study

以BCl_(3)为掺杂源的低压硼扩散炉是N型TOPCon太阳能电池重要制造设备之一,其工艺过程具有气体输送控制难、工艺气体腐蚀性强、反应洁净度要求高、尾气高温等特点。针对这些特点本文通过优化气路系统、增加气路伴热,保证BCl_(3)精准稳定;同时采用全石英炉门,增加背水冷法兰和风冷法兰,有效杜绝了金属离子污染,提高了太阳能电池的少子寿命及效率;另一方面通过全包裹水冷设计、双滤芯过滤以及水洗功能,滤芯更换周期及真空泵使用寿命提高了1倍。此外本文也研究了不同插片方式下扩散方阻及不良率,相比顺气流竖直插片方式,水平插片方式同一小舟内上中下硅片的扩散方阻极差大,制成电池后黑边不良比例低。

Low-pressure boron diffusion device with BCl_(3) as doping source is one of the important manu-facturing equipment of N-type TOPCon solar cells.Its process features uneasy control of gas transporta-tion,strong corrosiveness of process gas,high requirement in reaction cleanliness and high-temperature tail gas.In view of such characteristics,this paper optimizes the gas path system and adds the gas path heat tracing to ensure the accuracy and stability of BCl_(3).At the same time,the full-quartz furnace door adopted and the water-cooled flange and air-cooled flange added can effectively eliminate metal ion con-tamination and improve the minority carrier life as well as the efficiency of solar cells.Moreover,the full-wrapped water cooling,filter element filtration and wash function doubles the filter element replacement cycle and the service life of the vacuum pump.This paper also studies the diffusion square resistance and defect rate under different insertion methods.Compared with the downstream vertical insertion method,the horizontal insertion method has the advantages of large diffusion square resistance range of the upper,middle and lower silicon wafers in the same quartz boat,and low black-edge defect rate after they are made into battery.