| 摘要 |
PURPOSE:To obtain a semiconductor device having stable characteristics by forming oxide films on both the front and the back surfaces of N<->N<+> type substrate, forming a base region and an emitter region on the back surface after preforming a polycrystalline film thereon and removing the polycrystalline film after high temperature heat treatment such as diffusion or the like is finished. CONSTITUTION:The oxide films 3, 4 are formed on the front and the back surfaces of the substrate 2, and then the polycrystalline film 19 is preformed on the back surface thereof. Subsequently, a photoresist film is formed thereon, the base region 7 and the emitter region 9 are formed thereon, and after the high temperature heat treatment such as the impurity diffusion of the substrate 2 is completed, the polycrystalline film 19 is removed therefrom. Thus, the semiconductor device having stable characteristics can be obtained with preferable workability. |
