| 摘要 |
Provided is a technique of improving the properties of a bipolar transistor. Described specifically, upon formation of a collector electrode around a base mesa by the lift-off method, a resist film is formed over connection portions between the outer periphery of a region OA 1 and a region in which the base mesa 4 a is formed, followed by successive formation of gold germanium (AuGe), nickel (Ni) and Au in the order of mention over the entire surface of a substrate so that the stacked film of them will not become an isolated pattern. As a result, the stacked film over the base mesa 4 a is connected to a stacked film at the outer periphery of the region OA 1 , facilitating peeling of the stacked film over the base mesa 4 a. In addition, generation of side etching upon formation of a via hole extending from the back side of the substrate to a backside via electrode is reduced by forming the backside via electrode using a material such as WSi which hardly reacts with an n type GaAs layer or n type InGaAs layer.
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