Study On Melt-Crucible Boundary Layer And Production Process In The Growth Of 300mm Single Crystal Silicon

With the development of photovoltaic industry, it will be an inevitable trend in the future production that the diameter of the monocrystal silicon trends to be larger. Recently, the semiconductor equipment represented by LSIC has been improved with the need for higher quality of Czochralski silicon. As one of the most important token parameters of the crystal quality in the crystal, the existence of oxygen is harmful to silicon wafer and the following solar products, so the control of oxygen content becomes an efficient measure of improving the crystal quality. Therefore, during large diameter monocrystalline silicon preparation, the study on the introduction mechanism and control method about oxygen and strictly controlling of oxygen distribution in silicon crystals is of great significance for improving the crystal quality. To this end, based on the theory breakthrough and the needs of the practical production, this thesis emphasizes the research of the melt-crucible boundary layer in melt during the production of Czochralski silicon with the large diameter of 300 mm.Due to the melt-crucible boundary layer cannot be measured directly.With the high cost of testing.So we have to use the research method of numerical simulation with the professional program named CGSim.The influence on the melt-crucible boundary layer by crucible rotation, argon flow rate, and the strength of convection around the crucible wall has been systematically analyzed. Using "Tangent method" to define the thickness of the melt-crucible boundary layer at the first time. With multiple sets of contrast test to prove its accuracy. We eventually obtain the optimal machining parameters by the results analysis about the oxygen content in the crystal, the crystal stress, the height of melt-crucible interface, and power of heater. At last we get the following conclusion:(1) Convection strength and melt convection type changed with the process parameters in the melt. The crucible-melt boundary layer thickness and crucible wall convection near the wall has a direct relationship.(2) The oxygen concentration increased in the melt and high oxygen concentration in the single silicon crystal with thin boundary layer thickness. It’s worse for quality of the silicon crystal. So, the better quality,the better melt-crucible boundary layer thickness.(3) When the crucible rotation 11rpm and argon flow velocity of 0.9m/s, beneficial to the production of high purity crystal,avoid defects such as broken crystal, given the growth of the crystal sufficient power.So, crucible rotation 11rpm and argon flow velocity of 0.9m/s is the best production technology.