| 摘要 |
PURPOSE:To improve the integration degree of elements in the IIL part, and to prevent the decrease in reverse current amplification factor, by a method wherein the surface concentration of a color region surrounding a base region and an injector region is made slightly smaller than that of the base region. CONSTITUTION:An N<+> buried layer 2 is provided between a P-type Si substrate 1 and an N<-> epitaxial layer 3. An N<+> diffused layer 16 of low concentration is provided by impurity diffusion from the surface of the epitaxial layer 3 toward the buried layer 2. The surface concentration of an N<+>-type color region 15 surrounding the base region 7 and the injector region in the diffused layer 16 is set slightly lower than that of the base region 7. The emitter electrode 14 of a reverse vertical NPN transistor constructed in the diffused layer can be led out by coming into ohmic contact with the color region 15. The region surrounding the base region 7 forms a structure of double-stage concentration with a concentration slightly lower and a concentration much lower than the surface concentration of the base region 7; thereby, the reverse current amplification factor is increased by increasing the withstand voltage of a linear part and upgrading the emitter injection efficiency of the IIL part. |
