| 摘要 |
PURPOSE:To improve an integration degree, by hoisting a lower diffusion layer on an up-and-down isolation region by half or more thickness of an epitaxial layer and performing diffusion and concurrently largely driving in a collector low resistance region and an IIL base region and next forming an upper diffusion layer on the up-and-down isolation region. CONSTITUTION:While a lower diffusion layer 24 is hoisted in advance by half or more thickness of an epitaxial layer 25, diffusion is performed and concurrently a collector low resistance region 34 and an IIL base region 26 are driven in and next an upper diffusion layer 27 is formed. Therefore, the upper diffusion layer 27 can be shallowed without limitation of the base region 26 and diffusion time can be shortened. Therefore' the lateral diffusion of the upper diffusion layer 27 can be suppressed and its surface occupation area can be much reduced. Breakdown strength of the lower diffusion layer 24 formed widely does not interrupt improvement of integration degree all on the surface of the epitaxial layer 25. |
