| 摘要 |
PURPOSE:To change the emitter density into a density higher than the base density, increase the current amplification factor, and minimize the excess accumulated carrier by a method wherein the higher density emitter region is provided just below a base region and on the surface of an N type epitaxial layer, and the inactive region is covered with an oxide film. CONSTITUTION:A thin epitaxial layer determined by the thickness of the second epitaxial layer 16 is formed at an I<2>L region, and a thick epitaxial layer determined by the sum of thicknesses of the first epitaxial layer 13 and the second epitaxial layer 16 is formed at the normal bipolar transistor region. Therefore, the bi-polar transistor can be formed at a high withstand voltage, and the I<2>L element can obtain a high current amplification factor because the emitter high density region 14 contacts the base 20. Besides, the current amplification factor can be increased by providing the high emitter region 14 under the base region 20 in the I<2>L, and the region except for the active region is covered with the oxide film 15, accordingly the generation of the excess accumulated carrier can be restrained. |
