Low Pressure Diffusion And Thermal Oxidation Of Monocrystalline Silicon Solar Cells

Compared with the traditional atmospheric diffusion,the technology of low pressure diffusion can increase the sheet resistance,and reduce the surface recombination and the cost of production of the solar cell.In the technology of thermal oxidation,dry oxygen instead of ozone can improve the denseness and uniformity of the silicon dioxide,and passivate the surface state,and increase the lifetime of photon-generated carriers.In this paper,the influence of low-pressure diffusion on the performance of the solar cell is firstly studied.The four-point probe tester is used to test the sheet resistance of the silicon under different contrast conditions.The measured data is analyzed by the control variate method.The result shows that the sheet resistance of center position is greater than the sheet resistance of the four sides.And low pressure diffusion can change the reaction rate by adjusting the temperature of each zone,and then change the sheet resistance of the silicon to increase the uniformity of the sheet resistance,and the unevenness is reduced from the 14.08% to 10.14%;In the technology of low pressure diffusion,the gas molecules has a strong penetrating power,so that the distance between the silicon is reduced and the output increases,from 118,000 pieces to 145,000 pieces in the day.UV test and solar cell efficiency test analysis found that the silicon of low-pressure diffused has lower reflectivity than the silicon of atmospheric diffusion,and the efficiency of photoelectric conversion is also higher.The average conversion rate has increased from the 19.8% to 20.35 %.The silicon dioxide manufactured by the technology of thermal oxidation was studied by photo-conductance technique.The influence of the time of oxidation,the amount of oxygen,the amount of nitrogen,and the temperature of oxidation on the passivation coating was analyzed.It was found that the lifetime would follow the oxidation time,the amount of oxygen,the amount of nitrogen,the oxidation temperature increase,and reaching a maximum,the minority lifetime begins to decrease.