Patent ID: 6080237
Filing Date: 2000-06-27
Classification: C30B

Abstract:
A method for the production of a dislocation-free silicon single crystal by the Czochralski method, which allows growth of a main body part of the dislocation-free silicon single crystal by immersing a seed crystal formed of dislocation-free silicon single crystal in a melt of silicon and thereafter pulling said seed crystal without recourse to necking, said production being effected under the following conditions:(a) a horizontal maximum length of the part of said seed crystal being immersed in said melt of silicon at the time of completion of said immersion is not less than 5 mm;(b) the part of said seed crystal to be immersed in said melt of silicon has been shaped by machining; and(c) at least any one condition selected from the group consisting of the following conditions (c1) through (c6) is satisfied;(c1) a leading end of the part of said seed crystal to be immersed in said melt of silicon is convexed downward;(c2) a Rmax value of surface roughness of the part of said seed crystal to be immersed in said melt of silicon is not more than 5 .mu.m, based on the reference length of 0.1 mm;(c3) the part of said seed crystal to be immersed in said melt of silicon has been etched;(c4) a concentration of a dopant contained in said seed crystal is not less than 1.times.10.sup.17 cm.sup.-3 ;(c5) an immersing rate of said seed crystal in said melt of silicon is not more than 2.8 mm/min; and(c6) a temperature gradient occurring in said seed crystal is not more than 10.degree. C./mm during the growth of the silicon single crystal.