A base contact section of a planar structure electrically connecting a base electrode
to a base region of a bipolar transistor is constructed of a repeating structure
in a plan view, in which a high impurity concentration region of the same conductivity
type as that of the base region and a region of the reverse conductivity type from
that of the base region or low concentration region of the same conductivity type
as that of the base region, arranged in an alternately manner starting with a high
impurity concentration region of the same conductivity type as that of the base
region from an emitter region side. With such a structure, accumulation of minor
carriers in the base contact section can be suppressed, a high switching speed
can be achieved and reduction in power consumption can be realized. Further, the
emitter region is formed in a configuration of a plurality of stripes and the base
region to which a base electrode is not connected is formed in each of the emitter
regions of a stripe pattern, thereby enabling not only a junction area between
the emitter regions and the base region to be increased with no space for the base
electrode provided but also a safe operation area to be wider.
