Single Crystal Furnace Magnetic Field And The Research Of Its Influence On The Crystal Growth

With the increasing maturity of semiconductor materials technology and semiconductor processing technology,and the need of the rapid development of modern electronic industry,we proposed the demand of "three high and one large" for the most basic of modern semiconductor manufacturing silicon materials,that is,high purity,high integrity and high uniformity.In the crystal growth process,the introduction of a magnetic field into the crucible is an important method to improve the crystal quality by suppressing the convection current.In this dissertation,for the main problem of the critical equipment of magnetic field in this method currently,we carry out a large-diameter magnetic field and do the research of its effects on crystal growth.The main contents are as follows:(1)We analyzed and researched temperature distribution in the melt crucible,melt convection and magnetic inhibition mechanism of melt convection starting from the basic principle of czochralski method of crystal growth.We found that there were four main convection of the crucible melt,and thermal convection was the main one which was the strongest,the role of the region's largest and mainly influenced near the upper part of the crucible wall melt region;cusp magnetic field center plane of the crucible wall radial component Brmax,a bottom wall and a central longitudinal component of the surface under Bzmax 20mm,the crucible wall of the longitudinal component of the magnetic field Bzmin were the key parameters.(2)Based on relevant theory we derive the theoretical relationship between cusp magnetic field strength(orthogonal magnetic field)and the equivalent micro-gravity acceleration,geff=(?·?0·g0)/(?2·?·?h2·B2),analytically calculated the key parameters of cusp magnetic field in equivalent low orbit satellite at microgravity environment,and got the design parameters effectively suppressing convection in the melt cusp magnetic field,Brmax for 400GS,Bzmax for 800GS and Bzmin less than 110GS.It provided a way to determine theoretically the key parameters for the cusp magnetic field.(3)Transverse and cusp magnetic field structure of MCZ-6000A-type monocrystalline furnaces and their electrical parameters were optimized to obtain the optimal design parameters of the magnetic field.Its main parameters were verified through experimental verification,and it's results showed that simulation method was correct,realistic and trusting.Provided a complete set of simulation methods for further design and field experience with a reference value of the parameter.(4)Proposed a kind of new shield structure of cusp magnetic having upper and lower magnetic permeability ring and the center magnetic permeability ring.This configuration can reduce the reluctance of the magnetic circuit,improve the magnetic efficiency of the coil and reduce the power consumption of magnetic field.In the same conditions of the others(coil current of 350A),it made the hook-shaped magnetic field Brmax strength increased 27.0%;in the same Brmax intensity(491GS),power consumption was reduced by 36%.To reduce the power consumption of the cusp magnetic field,it provided a new shield structure.(5)We presented a high-voltage,low-current and low-power consumption voltage-cusp magnetic field structure.It's magnetic distribution and properties of the law were identical with the existing cusp magnetic field.This magnetic field(2400 turns)as compared with the existing cusp magnetic field(120 turns),the strength at the same magnetic field Brmax(491.6GS),the magnetic field reduced from the original 19.5kw to 9.8kw,by 50%.It provided a new magnetic field structure for researching and designing consumption cusp magnetic field.(6)Through the crystal growth experiment to validate the parameters of the magnetic field,the results show that the theoretical relation between magnetic field strength and the equivalent micro-g is correct,realistic and fully availabal for the design the key parameters of magnetic field.It provids a theoretical basis and method for the design of key parameters of cusp magnetic field.