| 摘要 |
PURPOSE:To increase the dielectric strength between a substrate and a collector thereby to obtain an integrated circuit element with a high dielectric strength, by providing a low-density N<-> layer between a channel stopper and a collector buried layer. CONSTITUTION:Before a buried layer 10 is formed in a P type silicon substrate 8, an N type impurity layer 9 is formed with a density 1-2 figures smaller than that of a channel stopper. Then, an N type impurity buried layer 10 is formed which is higher in density but smaller in diffusion depth than the layer 9. Thereafter, an N type impurity-doped epitaxial layer 11 is grown, and the silicon on the surface of a portion on which a field oxide film is to be formed is etched. P type impurities are diffused to form a channel stopper 12 and subjected to a high-pressure oxidation to form a thick oxide film 13. Thereafter, a base, emitter and collector are formed. Thus, the dielectric strength between the collector and the substrate is determined by the impurity densities of the layer 9 and the substrate 8 thereby the dielectric strength becomes higher than that of the conventional element. |
