JPS649615A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make it possible to form a high impurity concentration region without crystal defects readily in the deep part of a substrate, by implanting silicon ions by a high dosing amount, forming a second amorphous layer reaching the surface of the substrate from a first amorphous layer, and continuing the amorphous layer in the deep part of the substrate to the surface of the substrate. CONSTITUTION:A through SiO2 film 2 and a resist film 3 are formed on a P<-> type Si substrate 1 by thermal oxidation and the like. With the resist film 3 as a mask, phosphorus (P<+>) ions are implanted by a high dosing amount through a hole 4 and the through SiO2 film 2, and a first amorphous layer 6 is formed. Then, silicon (Si<+>) ions with two kinds of implanting energies are implanted through the hole 4 in the resist film 3 by high dosing amounts. Thus, a second amorphous layer 7, which is continued to the surface of the substrate 1, is formed in the upper region of the first amorphous layer 6. Then, heat treatment is performed, and the P<+> implanted region is made active. Thus an (n) well 5 is formed. At the same time, the first and second amorphous layers 6 and 7 are recrystallized. Thus the crystalline property is recovered in the direction of an arrow 9 and reaches the surface. Therefore, crystal defects do not remain in the vicinity of the region, where the first amorphous layer 6 has been present.