It is an object of the present invention to provide an epitaxial wafer
with fewer pit defects in the epitaxial layer of a silicon
monocrystalline wafer that has been doped with arsenic. Pit defects tend
to occur when gas etching is performed prior to epitaxial film formation,
but this tendency is reversed and a sound epitaxial layer is obtained by
setting the crystal plane orientation to (100) and specifying the range
of the tilt angle for the angle .theta. in the [001] direction or [001]
direction or the angle .phi. in the [010] direction or [010] direction
with respect to the [100] axis.