It is an object of the invention to provide a semiconductor wafer obtained
by forming a semiconductor thin film with uniform resistivity on a main
surface of a semiconductor single crystal substrate of 300 mm or more in
diameter.
When a process gas is supplied to over a main surface of a silicon single
crystal substrate 12 in rotation in almost parallel to the main surface
thereof in one direction in a reaction chamber 10 through six inlet ports
18a to 18f disposed in width direction of the reaction chamber 10, H.sub.2
gas, a semiconductor raw material gas and a dopant gas are supplied onto
an area in the vicinity of the center of the main surface of the silicon
single crystal substrate 12 and an intermediate area thereof through the
inner inlet ports 18a and 18b and the middle inlet ports 18c and 18d, and
only H.sub.2 gas and the semiconductor raw material gas without the dopant
gas are supplied onto an area in the vicinity of the outer periphery
thereof from the outer inlet ports 18e and 18f. In such arrangement, a
dopant gas produced by the auto-doping phenomenon is supplied onto the
area in the vicinity of the outer periphery of the main surface of the
silicon single crystal substrate 12. For this reason, the dopant gases
from both sources are combined, thereby a concentration of the dopant gas
supplied over all the main surface of the silicon single crystal substrate
12 is almost uniform.
