| 摘要 |
PURPOSE:To improve the yield rate of production for the subject transistor by a method wherein the polycrystalline silicon layer on a base region is oxidized using a nitriding silicon mask and a diffusion is performed on an emitter region and a high density base region through the remaining polycrystalline silicon layer. CONSTITUTION:Boron is diffused on an N type wafer 41 using an SiO2 film 42 as a mask and a base region 44 is formed. Then, a polycrystalline silicon film 45 is formed, an Si3N4 film pattern 46 is covered on the emitter region and the high density base region, and the polycrystalline 45 is converted to a silicon oxide 45' by performing a heat treatment. Then, the Si3N4 film pattern 46' is removed, the SiO2 film containing As is coated and a patterning is performed. Subsequently, the above is heated in the atmosphere of boron and a diffusion is performed on the emitter region and the high density base region simultaneously. Accordingly, the relative positional relations of the high density base region and the emitter region can be determined by performing only one photoetching process and the deviation of mask is not generated. |
