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
OA1 and a region in which the base mesa 4a 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 4a is connected to a stacked film at
the outer periphery of the region OA1, facilitating peeling of the
stacked film over the base mesa 4a. 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.