SEMICONDUCTOR DEVICE COMPRISING A COMBINED BIPOLAR-FIELD EFFECT TRANSISTOR

摘要

A combined bipolar-field effect transistor RESURF device includes a lightly-doped epitaxial buried layer (16) of a first conductivity type located between a semiconductor substrate (11) of the first conductivity type and an epitaxial surface layer (18) of a second conductivity type opposite to that of the first. The doping concentration and thickness of the epitaxial surface layer (18) are selected in accordance with the REduced SURface Field (RESURF) technique. A highly-doped buried layer (14) of the first conductivity type may be provided in the substrate (11) where it meets the lightly-doped epitaxial buried layer (16). A highly-doped buried region (19) of the second conductivity type may be located beneath the base region (20) of the device and sandwiched between the epitaxial buried layer (16) and the epitaxial surface layer (18). The advantages of such a device include a substantially reduced <> resistance, a more compact and flexible configuration, improved switching characteristics, reduced base device current requirements, and improved isolation. The device may be further improved by providing a buried annular region (21) of the first conductivity type around and in contact with said buried region (19), and a surface adjoining annular region (23) of the first conductivity may be provided adjacent the base region (20).