Research on the process of LPCVD in TOPCon solar cell

CHEN Jun; ZHAO Zengchao; HUANG Jiabin; LI Ming; LI Bing; DENG Xinxin; LIU Xiangqi

doi:10.19996/j.cnki.ChinBatlnd.2025.04.007

Abstract：The interfacial oxide layer and polycrystalline Si-based layer of the TOPCon solar cell were fabricated by the method of LPCVD(low-pressure chemical vapor deposition)equipment.The relevant process of the related oxide layer,polycrystalline silicon layer,and phosphorus diffusion doping is studied.The uniformity of Poly-Si thickness at different positions throughout the quartz boat has been greatly improved through the dual process gas entry method at the furnace mouth position and the furnace center position.The experimental results indicate that a smaller backfill oxygen flow rate of 8 L/min during the preparation of the tunneling oxide layer during the process can more evenly distribute the oxygen atmosphere throughout the entire tube furnace,which improves the tunneling oxide layer at the tail of the tube furnace and enhanced its Lifetime performance.The Raman spectra of polycrystalline silicon grown at lower temperatures and higher pressures indicate a relatively low degree of crystallization.Under the conditions of 580℃,610℃,and 630℃,the higher the temperature,the higher the degree of crystallization and the faster the growth of polycrystalline silicon.However,the degree of crystallization of polycrystalline silicon grown under various conditions is consistent after phosphorus diffusion.In addition,the results show that adjusting the thickness of the tunneling oxide layer to allow the amount of phosphorus atoms through the oxide tunneling layer can improve the passivation effect.The thicker the polycrystalline silicon,the lower the surface concentration of phosphorus doping under the same conditions,and the higher the surface concentration of polycrystalline silicon layers with the same thickness at higher phosphorus diffusion annealing temperatures.