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 relates to a method of manufacturing a bipolar transistor on a semiconductor substrate (11) which is provided with a first, a second and a third layer (1,2,3) of a first, second and third semiconductor material respectively, all of a first conductivity type. A first portion of the second layer (2) is transformed into a buried isolation region (15) comprising a first electrically insulating material. A first semiconductor region (6) of the first conductivity type, comprising, for example, a collector region, is formed from a second portion of the second layer (2) adjoining the buried isolation region (15) and a portion of the first layer (1) adjoining the second portion of the second layer (2). Then a base region (7) is formed on the buried isolation region (15) and on the first semiconductor region (6) by transforming the third layer (3) into a second conductivity type, which is opposite to the first conductivity type.

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 relates to a method of manufacturing a bipolar transistor on a semiconductor substrate (11) which is provided with a first, a second and a third layer (1,2,3) of a first, second and third semiconductor material respectively, all of a first conductivity type. A first portion of the second layer (2) is transformed into a buried isolation region (15) comprising a first electrically insulating material. A first semiconductor region (6) of the first conductivity type, comprising, for example, a collector region, is formed from a second portion of the second layer (2) adjoining the buried isolation region (15) and a portion of the first layer (1) adjoining the second portion of the second layer (2). Then a base region (7) is formed on the buried isolation region (15) and on the first semiconductor region (6) by transforming the third layer (3) into a second conductivity type, which is opposite to the first conductivity type.