Abstract
The effects of the growth conditions on the solid-liquid interface shape during the Czochralski growth of Cu crystals have been investigated. It is found that the interface shape is convex towards the melt in all cases, although the degree of the convexity of the interface varies with the growth conditions; the main results are as follows: (1) The degree of interface convexity increases with a decrease of the crystal radius. (2) The degree of interface convexity increases with an increase of the crucible rotation rate. (3) In a shoulder part of the crystal ingot, where its diameter increases, the degree of interface convexity is high, but it changes to a low value in the next part of the ingot where the diameter is constant. (4) The degree of interface convexity is almost independent of the growth rate. (5) A forced convection by Ar gas near the growing interface has little effect on the solid-liquid interface shape.
Moreover, the effect of the degree of the interface convexity on the crystal perfection has been examined. It is shown that the degree of crystal perfection is probably related to the thermal stress which arises from the convexity of the solid-liquid interface.
