摘要 |
PURPOSE:To realize the higher-speed operation of a bipolar transistor structure by a method wherein the capacitance between a non-active base region and a semiconductor substrate is reduced by an oxide layer formed on the semiconductor substrate. CONSTITUTION:A bipolar transistor 10 is composed of a semiconductor substrate 12, a subcollector region 14, an oxide layer 16, a collector region 18, an active base region 20 and an emitter region 22; an inactive base region 24 is situated on the oxide layer 16 and is connected to the active base region 20. Because the inactive babe region 24 is isolated from the subcollector region 14 by the oxide layer 16, the capacitance between the inactive base region 24 and the subcollector region 14 is reduced sharply. As a result, an electric charge quickly flows into or flows from the active base region; the transistor 10 can function at a high frequency.
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