Abstract: The bipolar transistor comprises a collector region (1) of a semiconductor material having a first doping type, a base region (2) of a semiconductor material having a second doping type, and an emitter region (3) having the first doping type. A junction is present between the emitter region (3) and the base region (2), and, viewed from the junction (4), a depletion region (5) extends into the emitter region (3). The emitter region (3) comprises a layer (6) of a first semiconductor material and a layer (7) of a second semiconductor material. The first semiconductor material has a higher intrinsic carrier concentration than the second semiconductor material. The layer (7) of said second semiconductor material is positioned outside the depletion region (5). The second semiconductor material has such a doping concentration that Auger recombination occurs. The invention also relates to a semiconductor device comprising such a bipolar transistor.

Abstract: The invention relates to an essentially discrete semiconductor device comprising a semiconductor body (10) having a first, preferably bipolar, transistor (T1) with a first region (1) forming a collector (1) of T1, and a second, preferably also bipolar, transistor (T2) with a second region (2) forming a collector (2) of T2, which transistors (T1, T2) are in a cascode configuration wherein the collector (1) of T1is connected to the emitter (4) of T2. Such a device cannot suitably be used in a base station for mobile communication. According to the invention, the first region (1) and the second region (2) are positioned next to each other within a semiconductor region (5), a part of which situated below the first region (1) is provided with a higher doping concentration at the location of T1. In this way, T1 has a low collector-emitter breakdown voltage and a high cutoff frequency, whereas for T2 said voltage and frequency are, respectively, high(er) and low(er).

Abstract: The bipolar transistor comprises a collector region (1) of a semiconductor material having a first doping type, a base region (2) of a semiconductor material having a second doping type, and an emitter region (3) having the first doping type. A junction is present between the emitter region (3) and the base region (2), and, viewed from the junction (4), a depletion region (5) extends into the emitter region (3). The emitter region (3) comprises a layer (6) of a first semiconductor material and a layer (7) of a second semiconductor material.

Abstract: The bipolar transistor comprises a collector region (1) of a semiconductor material with a first doping type, an emitter region (2) with a first doping type, and a base region (3) of a semiconductor material with a second doping type, opposite to the first doping type, which base region is arranged between the emitter region (2) and the collector region (1), and a semiconductor area (4) extending between the collector region (1) and the base region (3).

Abstract: A method of manufacturing a semiconductor device comprising heterojunction bipolar transistors (HBTs), in which method a first semiconductor layer of monocrystalline silicon (5), a second semiconductor layer of monocrystalline silicon comprising 5 to 25 at. % germanium (6) and a third semiconductor layer of monocrystalline silicon (7) are successively provided on a surface (2) of a silicon wafer (1) by means of epitaxial deposition. Base zones of the transistors are formed in the second semiconductor layer. In this method, the second semiconductor layer is deposited without a base doping, said doping being formed at a later stage. Said doping can be formed by means of an ion implantation process or a VPD (Vapor Phase Doping) process. This method enables integrated circuits comprising npn-transistors as well as pnp-transistors to be manufactured.

Abstract: The invention relates to an essentially discrete semiconductor device comprising a semiconductor body (10) having a first, preferably bipolar, transistor (T1) with a first region (1) forming a collector (1) of T1, and a second, preferably also bipolar, transistor (T2) with a second region (2) forming a collector (2) of T2, which transistors (T1, T2) are in a cascode configuration wherein the collector (1) of T1 is connected to the emitter (4) of T2. Such a device cannot suitably be used in a base station for mobile communication.