| 摘要 |
PURPOSE:To manufacture a semiconductor device with high DC amplification factor characteristics and improved leakage current withstand voltage characteristics by a method wherein the high concentration outer base is formed in a selfalignment mode not to diffuse in the low concentration inner base and emitter. CONSTITUTION:A low concentration P type region 6, an oxide film 2, a silicon nitride film 4 and a poly Si layer 5 are formed on a substrate 1. When a poly Si layer 7 provided on the overall surface is dryetched with intensive anisotropy, the layer 7 is etched in the vertical direction only to leave the poly Si layer 7 on the sides of layer 5 in selfalignment mode. Next, when B ions are implanted in high dose using layers 5, 7 as masks, high concentration P type regions 8 to be the outer base reducing base resistance are formed in a selfalignment mode from the ends of layer 7 without diffusing in the region 6. Later, an emitter 12, etc., in a high concentration N type region is isolated from the regions 8 and formed through the intermediary of oxide films 9, etc., so that a bipolar transistor, etc., at high concentration and operable at high speed with high leakage current and breakdown strength characteristics easy to control DC amplification factor by impurity concentration in the region 6 to be the inner base may be manufactured.
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