| abstract |
A bipolar transistor of type NPN has an active region at the surface of the component, which is surrounded, as seen along the surface of the component, in the conventional way by thick field oxide areas (18). The active region is partly covered by an electrically isolating surface layer, preferably comprising a nitride layer (34). A base region in the active region is defined by a well-defined opening, which is lithographically produced, in the electrically isolating surface layer. For a bipolar lateral transistor of type PNP, which instead has emitter and collector regions surrounded by such thick field oxide areas, the emitter and collector regions can in the corresponding way be defined by a lithographically defined opening in an electrically isolating surface layer. Owing to the well defined openings the base-collector capacitance and the emitter-collector capacitance respectively can be reduced in these cases, what results in better high frequency characteristics of the transistors. A region of the silicon nitride layer(34) is at the same time used as an efficient dieletric in a simultaneously manufactured capacitor. The NPN-transistor can be provided with a thin side string made of nitride for isolation between an emitter connection and a base connection. In the same semiconductor plate special, deep and shallow substrate connecting terminals can be provided for electrically isolating component areas. Trenches (22) can be used for electrical isolation of component areas and they can at their sidewalls have a laminate of at the bottom oxide (23) and thereon nitride (25) in order to facilitate planarizing etching and in order to act as a diffusion barrier. |