| 摘要 |
PURPOSE:To determine an arbitary and large value of an emitter resistance without being limited by the composition of an emitter, by a method wherein the emitter and the emitter resistance are made independent each other by taking the emitter electrode out of a semiconductor substrate and composing the emitter resistance with the substrate. CONSTITUTION:A P<+> layer 110 and an epitaxial layer 111, which is piled on the layer 110, compose a substrate 11. The layer 111 is utilized as an emitter resistance and its value is arbitrarily determined at a value not more than 100ohms by controlling the specific resistivity and the thickness. An N buried layer 12 is provided and an epitaxial layer 13 is piled over it. The epitaxial layer 13 is devided by a P layer 15, and a collector, layer 14 is segmented. The N<+> layer 19 are provided and connected to the buried layer 12. In the N collector 14, a P base 16 and an N emitter 17 are produced. The surface is covered by an SiO2 film 20, in which an aperture is made. Al electrodes 21, 22, the P layers 15 and a connecting conductor 18 of the N emitter 17 are connected to the N<+> layers 19 and the P base 16. The electrode 23 of the emitter resistance is connected to the main surface of the substrate and the device is completed. The transistor produced by above method has such characteristics that hFE drops rapidly in accordance with large collector current and can provide excellent current limiting function. |
