| 摘要 |
PURPOSE:To obtain readily the semiconductor device having high performance and small base layer by forming an etched groove at the polysilicon by utilizing a gap formed in the boundary between an Si3N4 mask and an SiO2 mask and isolating a base connecting layer and an emitter connecting layer. CONSTITUTION:A no-addition polysilicon film 4 is accumulated on a p type layer 3 and an SiO2 film 2 of an n type Si 1, the Si3N4 mask 5 is covered thereon, is thermally oxidized, and an SiO2 film 10 is formed. When the film 10 is lightly etched, a gap 10A is formed in the boundary between the films 10 and 5. Then, the polysilicon 4 is etched by alkaline etchant, and a groove 4A is formed. The film 10 is etched, ions are injected thereto, a p<+> type base connecting layer 4' is formed, is thermally oxidized, and an SiO2 film 7 is formed thereon. The mask is removed, ions are injected thereto, and an n<+> type emitter connecting layer 4'' and an n<+> type emitter layer 8 are formed. Finally, windows are opened at the insulating film 7, and electrodes 9E, 9B are attached therethrough. According to this configuration it can eliminate the difficult control of forming the groove by sidewise etching of the Si3N4 film, and the device having preferable characteristics and integrity can be readily obtained. |
