Improvement Of Φ8" Hot Zone For Φ8" CZSi And The Numeric Simulaion

With the rapid develop of science, proceed from the exaltation of productivity and the decline of cost, the device factory will enlarge the diameter of wafer gradually along with the extension of production scale. To the large diameter of Si single crystal, the big volume of melt and serious hot convection makes the oxygen content of the single crystal enlargement. The increase of the crystal diameter also makes the release of the crystallize latent heat and the exaltation of the crystallize velocity more difficult. In this paper, for solving these two problems, we modified the hot zone of the homemade TDR-80 single crystal furnace and installed the new compound heat shield.FEM (finite element method) is the most important numeric method. FEM has become an important way to research the crystal growth. Because of the large stuff of silicon, complex structure of furnace and expensive cost, computer simulation is a best way to optimize design. The simulation was made on the compound hot zone. The argon flow velocity distribution and the temperature distribution of the hot zone were showed. The affect of the new heat shield and short heater on the crystal growth were analyzed.As a result, the new heat shield can equal to a guide shell and improve the argon flow field, leads to the descent of the crystal oxygen concentration. However, the heatt shield resolves the release problem of the crystallize latent heat in large diameter single crystal growth, the pull speed is enhanced to a great extent, the production cost becomes lower. This paper provides the more substantial experiment proof for the large diameter crystal growth theory.