Study On The Magnetic Field Growth Technique And Oxygen Incorporation Mechanism In The CZ Single Crystal Silicon

Single crystal silicon is widely used in photovoltaic power generation system and the microelectronics field.With the rapid development of industry,single crystal silicon toward the direction of the large diameter,high quality and low cost.For large diameter single crystal silicon production,the diameter of the crucible,and inventory is bound to increase,more intense convection in the melt in complex and difficult to control,and magnetic field pulling technique to control severe convection is more complex.In this paper,the structure of the cusp type magnetic field is studied,and the optimal magnetic field structure is determined.On the basis of the best magnetic field,the influence of the process parameters on the quality of the crystal is studied.In addition to improving the quality of crystal,oxygen content in the crystal is one of the important parameters,and the oxygen impurity mainly comes from the thermal decomposition,the crucible wall is then transport to the solid-liquid interface and segregated to crystal,and the boundary layer is the important place to oxygen segregation.This paper further solve the analytical solution of the boundary layer thickness,which in solid-liquid interface with mechanism of the distribution situation of the research of oxygen and it is also the innovation point of this paper.The results of this simulation are as follows:(1)As the spacing of the upper and lower coils(H)increase,the pressure convection intensity increase under the crystal,and the center deflection of the solid-liquid interface increase.When H is large,the thickness of the oxygen boundary layer is more uniform in the solid liquid interface,which is beneficial to the uniform distribution of oxygen in solid liquid interface.With the decrease of the magnetic field ratio(MR),lorentz forces have a stronger effect on the melt,and the convection intensity decreases in the melt.When the magnetic field is closer to 1,the thickness of the oxygen boundary layer is more uniform in the solid liquid interface.(2)With the increase of the number of crystals,the convection intensity of the melt is increasing gradually,and the center deflection of the solid-liquid interface increases gradually.When the number of crystals is 6rpm,8rpm and 12rpm,the thickness of the oxygen boundary layer is evenly distributed.As the value of the pot goes up,the temperature of the cauldron rises.Deflection value of the solid-liquid interface center is gradually decreasing,and the thickness of the oxygen boundary layer is proportional to the number of the rotary.(3)The temperature of the wall of the crucible decreases as the speed of the growth rate increase,and the solid-liquid interface is shaped by a convex type.The boundary layer thickness of the oxygen boundary is inversely proportional to the growth rate value,and the oxygen boundary layer of the oxygen boundary layer is relatively smooth when the pull speed is 65mm/h.