MANUFACTURE OF SEMICONDUCTOR DEVICE

PURPOSE:To restrain a P-type impurity from being diffused thermally, to control a P-type semiconductor region to a shallow region from the surface of a semiconductor substrate and to form this region in a more activated state by a method wherein an N-type impurity and the P-type impurity exist together in a polycrystalline silicon film. CONSTITUTION:An insulating film 2 such as a silicon oxide film or the like is formed on an N-type silicon substrate 1; after that, the insulating film 2 is removed selectively; a diffusion hole 3 is made in such a way that the surface of the substrate 1 is exposed. Then, a polycrystalline silicon film 4 is deposited on the surface of the exposed substrate 1 and on the insulating film 2. Then, boron is implanted into the whole surface of the layer 4. In addition, arsenic is implanted into the whole surface of the layer 4. During this process, implantation energy is selected properly, and ions are implanted in such a way that the boron and the arsenic exist only at the inside of the layer 4. After that, a heat treatment is executed; the boron and the arsenic are diffused into the substrate 1 from the layer 4; a P-type impurity diffusion region 5 and the N-type impurity diffusion region 6 are formed. Thereby, the region 5 can be formed in a shallow region from the surface of the substrate 1.