摘要 |
PURPOSE: A bipolar transistor is provided to increase an output power while minimizing a decrease of an operation frequency, and to reduce manufacturing cost by decreasing a device area in a condition of given operation frequency and output power. CONSTITUTION: A main axis(2-3) is composed of a polygon having a bar type so that a circumference/area value of an emitter planar structure(2-1,2-2) is increased to improve a current driving capacitor of the emitter of the bipolar transistor. A plurality of branches(2-4) of a polygon are connected to the main axis. At least one side of the polygon of the branch is a roughness type.
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