Shape and quality of Si single bulk crystals grown inside Si melts using the noncontact crucible method

The noncontact crucible method enables production of Si bulk single crystals without crucible contact by intentionally establishing a distinct low-temperature region in the Si melt. In this contribution, we correlate crystal growth conditions to crystal material properties. The shape of the growing interface was generally convex in the growth direction. The quality of the Si ingots was determined by the spatial distributions of dislocations, resistivity, oxygen concentration, and minority-carrier lifetime. In an ingot with a convex bottom, swirl patterns with higher resistivity are present in the top, middle, and bottom of the ingot. The dislocation density decreased from the top (first to solidify) to the bottom of the ingot because dislocations in the ingot moved to the periphery from the center of the ingot during crystal growth owing to the convex growing interface. The oxygen concentration was concentrically distributed on the seed axis owing to the convex growing interface. The lifetime was as high as 1.8ms after phosphorus diffusion gettering (PDG) and 205 μs before PDG at an injection level of 1 × 10¹⁵cm^-3. The lifetime was not strongly affected by the dislocation density, which was as low as 10²-10³cm^-2.