Numerical Analysis Of The Effect Of Single And Double Induction Coils On The Growth Of 6-inch SiC Crystals

The growth of SiC crystal is quasi-closed and the growth temperature exceeds 2000 °C.It is difficult to observe the thermal field and crystal growth process inside the crucible in real time.With the crystal diameter from 4 inches to 6 inches,the radial temperature gradient and the thermal stress generated in the crystal also increases,the defects proliferate,and the yield decreases.In this paper,the influence factors of the internal thermal field of 6-inch SiC crystal growth were systematically studied by Virtual Reactor software simulating the growth of SiC crystals.The influence of the structure of the crucible,thermal insulation layer and induction heating coil on the thermal field was analyzed in depth.The effect of the double induction coils on the internal thermal field and crystal growth quality has been investigated compared with single induction coil.The main research contents and conclusions of this paper are as follows:1.The influences of the crucible,thermal insulation layer structure and coil structure on the thermal field of single coil induction heating has been investigated.The results show that increasing the height of the crucible or the distance of the material surface,decreasing the thickness of the crucible wall or the diameter of the blind hole on the crucible lid,the radial temperature gradient will decrease;increasing the thickness of the crucible wall or the material surface,reducing the diameter of the blind hole on the crucible lid or the height of the crucible the axial temperature gradient will decrease;the thickness of the insulation layer will increase,the axial temperature gradient will decrease,and the crystal growth power consumption will be significantly reduced;The coil structure will change the position of the high temperature region and therefore affect the heat field in the crucible.2.The influence of the coil structure on the thermal field under the induction heating of the double coil is studied and the structure is optimized.The results show that with double coil induction heating,the radial temperature gradient in the thermal field of SiC crystal growth is2.52 °C / cm,the axial temperature gradient is 4.42 ° C / cm.Compared to single coil induction heating,the radial temperature gradient and axial temperature gradient are reduced by 10.9% and 1.7%,respectively.3.The effects of single and double coil structures on crystal growth are studied.The results show that the double coil induction heating structure can significantly improve the crystal quality.Compared with the crystal in the single coil induction heating structure,the maximum stress and maximum dislocation density in the crystal are reduced by 16.8% and72.9%,respectively.