Abstract: An apparatus for making a silicon single crystal large in diameter dependently on the Czochralski process, wherein appropriate openings (11) are provided on the warmth keeping over (10) so as to prevent an undesirable influence caused by atmospheric gas. The major elements of the apparatus are that the sum of areas of the openings (11) is larger than the area of gap (18) formed between the lower end of the warmth keeping cover (10) and the level of silicon solution, and that the warmth keeping cover and the heat insulating member (12) are composed of sheet metal.

Abstract: A crucible including a cylindrical partition member arranged concentrically therein for use in a silicon single crystal growing apparatus. The bottom of the crucible located on the inner side of the partition member has a thickness which is not less than 1.3 times and not greater than 4 times the thickness of the partition member and it also has a porosity which is between 0 and 0.2% in its inner layer and between 0.2 and 15% in its outer layer as compared with the porosity of the partition member which is 0.2% or less. By virtue of the foregoing, a D.F. ratio (ratio of dislocation free) of 80% or over can be expected.