| 摘要 |
PURPOSE: A bipolar transistor is provided to increase area of an emitter region by rounding the surface of the emitter region. CONSTITUTION: A bipolar transistor comprises a semiconductor substrate(20), an oxide pattern(22), an emitter region(24), and an emitter electrode(26). The oxide pattern(22) is formed on the semiconductor substrate(20) to expose emitter formation region, and impurities are implanted to the exposed emitter formation region. The emitter region(24) is formed by diffusing the implanted impurities through applying a thermal energy. The surface of the emitter region(24) is rounded by lightly etching. Thereby, the surface of the emitter region(24) has a spherical structure and then the surface area of the emitter region(24) is increased.
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