Quartz glass crucible for pulling a single crystal

An apparatus for pulling silicon single crystal comprising:

• a quartz glass crucible comprising:
• a cylindrical straight wall portion including a first area having a height corresponding to about 75% or less of the total height of the crucible, measured from an upper open end of the crucible, the first area comprising across its entire thickness an opaque material having a total volume of bubbles ranging from about 7.times.10.sup.-3 cm.sup.3 /cm.sup.3 to 30.times.10.sup.-3 cm.sup.3 /cm.sup.3 ;
• a bottom wall portion;
• and
• a curved intermediate wall portion connecting the straight wall portion and the bottom wall portion;
• the straight wall portion further having a second area, wherein said second area, said curved intermediate portion and said bottom portion are comprised of two layers, the first layer of which comprises an inner transparent layer having a total volume of bubbles of about 4.times.10.sup.-3 cm.sup.3 /cm.sup.3 or less and corresponding to from about 20% to 60% of the total thickness of the crucible wall measured from the inside surface thereof, and the second layer of which comprises an outer layer comprised of an opaque material having a total volume of bubbles ranging between about 7.times.10.sup.-3 cm.sup.3 /cm.sup.3 and 30.times.10.sup.-3 cm.sup.3 /cm.sup.3 ;
• a holder contacting the quartz glass crucible for holding the crucible;
• a heater surrounding the quartz glass crucible and the holder;
• and
• a chamber in which the quartz glass crucible is provided, the chamber being able to provide an airtight internal space.