| 摘要 |
PURPOSE:To prevent the deviation of patterns of various layers, by forming an active base and a graft base by using one kind of a photo mask by a single diffusing process, and forming a base layer and an emitter layer by using a self-aligning method utilizing polycrystalline silicon. CONSTITUTION:On a substrate 1, an n type epitaxial layer 3 provided with an n type embedded layer 2 is formed. An element forming region is separated by a p type isolating diffused layer 4. A polycrystalline silicon film is grown thereon. A polycrystalline silicon layer 12 is formed. Then, a silicon dioxide film 10 and a silicon nitride film 13 are formed. Thereafter a hold is provided through the silicon nitride film 13 and the polycrystalline silicon layer 12 in the sameshape. A hole is provided in the silicon dioxide film 10. After the silicon nitride film 13 is removed, boron is diffused. Thus an active base layer 6a and a grafd base layer 5a are simultaneously formed. The oxide film on the polycrystalline silicon layer 12 is removed. Phosphorus is diffused through the polycrystalline silicon layer 12. An n type emitter layer 7a is formed, and an n type collector contact layer 8a is simultaneously formed. |
