SEMICONDUCTOR DEVICE, AND ITS MANUFACTURE

PURPOSE: To prevent the diffusion of dopant to an insulating film around an emitter, and dispense with the reformation of an insulating film around the emitter, and further, facilitate the removal of the needless part of a base electrode film. CONSTITUTION: A collector layer 2, a base layer 3, an emitter layer 4, a first WSi film 5, and an Al film 6, a second WSi film 7 are made in order on a semiconductor substrate, and then each layer 4-7 is partially etched anisotropically to form a groove, and this groove is stopped with a second insulating film 9. Then, using a resist over in size than an insulating film 9 as a mask, only each layer 4-7 outside the insulating film 9 is removed, and a solid-phase diffusion source is made all over the surface. Furthermore, with the thermally flagged resist as a mask, a solid-phase diffusion source is removed partially, and a processed solid-phase diffusion source 14 is made. After a third insulating film 15 is made all over the surface, a high-carrier concentration area 16 is made by heat treatment. After that, the third insulating film 15 and the solid-phase diffusion source 14 are removed, and a base electrode film is made all over the surface, and a needless part is removed.