Indexed by:期刊论文

Date of Publication:2018-02-01

Journal:MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING

Included Journals:SCIE、EI、Scopus

Volume:74

Page Number:102-108

ISSN No.:1369-8001

Key Words:Silicon ingot; Directional solidification; Temperature gradient; Diffusion layer thickness

Abstract:The diffusion layer thickness of impurity during directional solidification process was evaluated under different temperature gradient conditions. The thickness of Fe, Cu, Ni and Ti in silicon ingot under 9.74 K/m were 6.19 mm, 4.92 mm, 4.61 mm and 8.70 mm, respectively; The thickness of Fe, Cu, Ni and Ti in silicon ingot under 28.49 K/m were reduced to 3.35 mm, 1.21 mm, 1.85 mm and 5.81, respectively. The diffusion layer thickness was reduced by the large temperature gradient to lead a low effective segregation coefficient. As a result, the impurity concentration of silicon ingot under 28.49 K/m was reduced to 0.94 ppmw. The strong vortex in the solid-liquid boundary interface was enhanced by the large temperature gradient, as the main transport mechanism to accelerate the diffuse of impurity atom in the diffusion layer, which effectively reduced the thickness of diffusion layer.