The present invention provides a silicon single crystal wafer having a diameter
of 300 mm or more and having a defect-free layer containing no COP for a depth
of 3 m or more from a surface and a method for producing a silicon single
crystal, wherein, when a silicon single crystal having a diameter of 300 mm or
more is pulled with nitrogen doping by the CZ method, the crystal is grown with
a value of V/G [mm2/Kmin] of 0.17 or less, where V [mm/min] is
a pulling rate, and G [K/mm] is an average of temperature gradient in the crystal
along a pulling axis from the melting point of silicon to 1400 C. Thus, there
are established conditions for pulling a silicon single crystal and conditions
for heat treatment of wafer for obtaining a silicon single crystal wafer having
a defect-free layer free from COP for a sufficient depth of the surface layer by
pulling a silicon single crystal having a diameter of 300 mm or more, processing
the crystal into wafers and subjecting the wafers to the heat treatment.
