Abstract: The invention relates to a semiconductor device (10) with a substrate (11) and a semiconductor body (1) comprising a bipolar transistor with in that order a collector region (2), a base region (3), and an emitter region (4), wherein the semiconductor body comprises a projecting mesa (5) comprising at least a portion of the collector region (2) and the base region (3), which mesa is surrounded by an isolation region (6). According to the invention, the semiconductor device (10) also comprises a field effect transistor with a source region, a drain region, an interposed channel region, a superimposed gate dielectric (7), and a gate region (8), which gate region (8) forms a highest part of the field effect transistor, and the height of the mesa (5) is greater than the height of the gate region (8). This device can be manufactured inexpensively and easily by a method according to the invention, and the bipolar transistor can have excellent high-frequency characteristics.

Abstract: The invention provides a method for fabricating a heterojunction bipolar transistor with a base connecting region (23), which is formed self-aligned to a base region (7) without applying photolithographic techniques. Further, a collector connecting region (31) and an emitter region (29) are formed simultaneously and self-aligned to the base connecting region (23) without applying photolithographic techniques.

Abstract: A method of fabricating a bipolar transistor in a first trench (11) is disclosed wherein only one photolithographic mask is applied which forms a first trench (11) and a second trench (12). A collector region (21) is formed self-aligned in the first trench (11) and the second trench (12). A base region (31) is formed self-aligned on a portion of the collector region (21), which is in the first trench (11). An emitter region (41) is formed self-aligned on a portion of the base region (31). A contact to the collector region (21) is formed in the second trench (12) and a contact to the base region (31) is formed in the first trench (11). The fabrication of the bipolar transistor may be integrated in a standard CMOS process.