| 摘要 |
PURPOSE:To improve the characteristics of the minor signal circuit element for the subject device without deteriorating the characteristics of a power transistor by a method wherein a double-layer epitaxial layer, having different specific resistance, is provided. CONSTITUTION:In the bipolar type integrated circuit element wherein a power transistor and a minor signal circuit element are constituted on the same chip, an N<-> layer 22 of a high specific resistance is provided on an N type silicon substrate 21, and an N-layer 23 of a low specific resistance is epitaxially grown on the above N-layer 22. Subsequently, a P type base region 24 is formed at the section where the power transistor will be formed, and then an N type emitter 25 is formed. Also, the minor signal circuit element is provided on the other region of the N-layer 23 of low specific resistance. Then, a contact hole is opened on an insulating layer 26, a base electrode, emitter electrodes 27 and 28 are formed, and then a collector 29 is provided on the reverse side of the substrate. Accordngly, the characteristics of the minor signal circuit can be improved without deteriorating the withstand voltage characteristics of the power transistor. |
