Abstract: The invention provides a bipolar transistor with an improved performance because of a reduced collector series resistance and a reduced collector to substrate capacitance. The bipolar transistor includes a protrusion (5) which size may be reduced to a dimension that cannot be achieved with lithographic techniques. The protrusion (5) comprises a collector region (21) and a base region (22), in which the collector region (21) covers and electrically connects to a first portion of a first collector connecting region (3). A second collector connecting region (13) covers a second portion of the first collector connecting region (3) and is separated from the protrusion (5) by an insulation layer (10, 11), which covers the sidewalls of the protrusion (5). A contact to the base region (22) is provided by a base connecting region (15), which adjoins the protrusion (5) and which is separated from the second collector connecting region (13) by an insulation layer (14).