Patent ID: 7148557
Filing Date: 2006-12-12
Classification: H01L

Abstract:
1. A bipolar transistor comprising: a first semiconductor layer including an intrinsic base region and an extrinsic base region; a second semiconductor layer formed on the first semiconductor layer, wherein part of the second semiconductor layer located on the intrinsic base region forms an emitter region or a collector region; a capacitive film formed on the extrinsic base region of the first semiconductor layer; and a base electrode formed on the first semiconductor layer, wherein part of the base electrode is located on the capacitive film, and the other part of the base electrode is connected to the extrinsic base region adjacent the side of the capacitive film far from the intrinsic base region, a part of the capacitive film located under the base electrode serves as a depletion layer, and the capacitive film has a thickness of 300 nm or less and a width of 1 μm or more.