PURPOSE: To obtain the title process bringing about the trapping effect of needless impurity more powerful and reliable than any other conventional proc ess by a method wherein a getter layer containing respective specific two kinds of non-metallic elements is formed by ion-implanting the said elements in the rear surface side of the wafer.

CONSTITUTION: As for the formation of a getter layer 3 to trap any needless metallic impurity, etc., in danger of permeating into a wafer 1 in the wafer 1 comprising silicon for a semiconductor device, the getter layer 3 containing a nonmetallic element in larger ionic diameter than that of silicon and causing the misfit transition to a silicon crystal as well as another non-metallic element as an impurity providing the silicon with specific conductivity type is ion- implanted into the rear surface 1b side of the wafer l. For example, as for the first element in larger ionic diameter than that of the silicon for the getter layer 3, oxygen O is applicable likewise as for the second element to be com bined with O, phosphorus P is applicable while these two elements O and P in the state of monovalent-ion P2O3+ of the compound P2O3 are ion-implanted into the rear surface 1b of the wafer 1.