| 摘要 |
PURPOSE:To form both N type and P type impurity diffusion layers simultaneously without introducing defects and strain into a silicon substrate by using gallium as a P type impurity, forming an outward diffusion preventive film only on a polycrystalline or amorphous silicon layer in a region, into which ions are diffused, and thermally treating the whole. CONSTITUTION:An oxide film 2 is formed to the surface of an N<-> type silicon semiconductor substrate 1 by using a selective oxidation method, and the oxide film in a region in which an emitter must be formed is removed. Si4 is thermally decomposed on the surface of the silicon substrate 1, and a polysilicon layer 3 is grown at a low temperature. NH3 and SiH4 are reacted on the surface of the polysilicon layer 3, and a silicon nitride film 6 is grown at a low temperature. The silicon nitride film in regions except a region in which a base must be formed is removed. A P base layer 4 and an N<+> emitter layer 5 are shaped simultaneously in the silicon substrate 1 through heat treatment in a nitrogen atmosphere. Polysilicon in regions except polysilicon 3 on the N<+> emitter layer 5 is removed, and windows for contacts of the P base layer 4 and the N<+> emitter layer 5 are bored. |
