| 摘要 |
PURPOSE:To reduce the resistance of a base-electrode taking out part, by providing a protruded part in an N type drift region, sequentially growing a base region and an emitter region by an epitaxial method, and making the thickness of the lower part of the epitaxial layer thicker than that of the protruded part. CONSTITUTION:On a high concentration N type GaAs substrate 21, an N type GaAs layer 22 is grown. The N type GaAs layer 22 is selectively etched so that a base region is protruded. Thus a protruded part 22a is formed. Then, by using a liquid phase epitaxial method, a P type GaAs layer 23, an emitter region 24 and an N type GaAs layer 25 are sequentially grown on the N type GaAs substrate having the protruded part. The thicknesses of the P type base layer 23, the N type AlXGa1-XAs emitter layer 24 and the N type GaAs layer 25 for an emitter electrode over the protruded part are thin. The thicknesses of the lower peripheral parts of said layers are thick. Thereafter, the N-GaAs layer 25 and the N-AlXGa1-XAs layer 24 are partially removed so that a part of the base region 23 is exposed at the lower parts. Then a base electrodes 27 are formed, and the emitter electrode 26 is formed on the protruded part. |
