| 摘要 |
PURPOSE:To reduce an ineffective base current and effectively increase the current amplification factor of vertical transistors of an I<2>L device, by providing a prescribed layer of high impurity concentration, only under the collector region of the vertical transistors. CONSTITUTION:An n-type embedded layer 32 and an n-type epitaxial layer 33 are provided on a p-type Si substrate 31. Windows are opened, only under portions to be the collector regions of vertical transistors. n<+>-Type embedded layers 34 of higher impurity concentration than the n-type layer 33 are produced by diffusion. An epitaxial layer 35 is produced on the embedded layers 34. At that time, the layers 35, 33 so that layers penetrating emitter-base junctions are provided. An emitter region 36 and a collector region 37 are then produced. Since the high-concentration n<+>-type layers 34 are present only on base-emitter junction portions facing the collector regions 38 of the vertical transistors of an I<2>L device, base currents flow through the layers 34. This results in reducing an ineffective current and increasing the current amplification factor. |
