Research Progress on Influencing Factors of Dislocation in Czochralski Silicon

Based on the introduction of the dislocation formation and movement mechanism in Czochralski silicon, the effects of seed crystal thermal shock, solid-liquid interface, crystal diameter, and impurities on the dislocations during the crystal growth process were summarized. The effects of boron, germanium, nitrogen, phosphorus, arsenic doping elements and oxygen impurities on the dislocation behavior of the Czochralski silicon were analyzed. The thermal shock of the seed crystal can lead to the dislocations, which can be suppressed by some methods such as necking, melting back, seed crystal preheating, and the use of doped seed crystal. The solid-liquid interface convex to the melt causes a large edge shear stress to produce the edge dislocations. The formation of dislocations can be suppressed when the shape is flat. In heavily n-type doped single crystal silicon, the evolution of solid-liquid interface and the formation of {111} edge surface may promote the generation of supercooling region and interrupt the growth of top cone, thereby causing the dislocations, and the length of the edge surface is related to the curvature of the melting isotherm. Incomplete seeding of the seed crystal will produce the dislocations that cannot be discharged from the crystal, and then extend to the silicon rod. The increase in the diameter of single crystal silicon and the fluctuation of the diameter during the crystal growth process will increase the risk of dislocation formation. Doping is an effective method to inhibit the formation and movement of dislocations. Boron, germanium, nitrogen, phosphorus, arsenic and oxygen impurities all have different degrees of inhibition on the dislocations mainly due to the pinning effect of impurity atoms on the dislocations. Finally, some future research aspects on necking process, thermal field design, doping process and theoretical modeling were prospected. © 2021, Editorial Department of Journal of the Chinese Ceramic Society. All right reserved.