| 摘要 |
PURPOSE:To obtain a hetero-junction bipolar transistor operating at ultra-high speed by selectively purifying only the exposed section of a base layer and forming a semiconductor layer containing an impurity, which is changed into a single crystal on the surface of the base layer and into a polycrystal or amorphous on the surfaces of emitter and collector layers and obtains the same conduction type as the base layer. CONSTITUTION:Layers are etched up to an N-type Al0.3Ga0.7As collector layer 2 so that an operating region in a transistor is left and a P-type GaAs base layer 3 is exposed to a side surface. A natural oxide film only on the surface of the P-type GaAs base layer 3 in natural oxide films adhering on the surfaces is removed. When GaAs containing Be is grown in an MBE manner under the state, P-type GaAs grows in a single crystal on the surface of the P-type GaAs base layer 3 having no natural oxide film. On the contrary, polycrystalline GaAs having high resistance is shaped on the surfaces of the N-type Al0.3Ga0.7As collector layer 2, on which the natural oxide film is left, and an emitter 4. One parts of an insulating region 10 in the upper sections of the collector layer 2 and the emitter layer 4 are removed by etching to form a collector electrode 6, base electrodes 7 and an emitter electrode 8, thus completing a hetero-junction bipolar transistor through alloying. |
