Patent ID: 6441446
Filing Date: 2002-08-27
Classification: H01L

Abstract:
A device with a bipolar transistor and a MOSFET transistor connected to one another in the â€œemitter switchingâ€  configuration and integrated in a chip of semiconductor material, comprising:a substrate with a first type of conductivity and with a high concentration of impurities; a layer with the first type of conductivity, superimposed on the substrate and having a concentration of impurities lower than that of the substrate, wherein the layer and the substrate comprises a collector region of the bipolar transistor; a first electrically conductive surface contact element which extends on the surface of the substrate remote from the layer and has the function of a collector electrode of the bipolar transistor; a region with a second type of conductivity and with a low concentration of impurities, buried in the layer with the first type of conductivity and forming a base region of the bipolar transistor; a base contact and insulation region with the second type of conductivity and with a high concentration of impurities, which extends from a front surface of the chip, that is, from a surface of the chip opposite to the collector terminal, as far as an edge of the region with the second type of conductivity; an insulated region with the first type of conductivity defined within the base contact and insulation region; a second electrically conductive surface contact element on the base contact and insulation region, with the function of a base electrode of the bipolar transistor; a region with the first type of conductivity and with a high concentration of impurities, which is buried in the insulated region, forms a pn junction with the base region, and comprises an emitter region of the bipolar transistor, a further region with the second type of conductivity which extends from the front surface of the chip in the insulated region and comprises a channel of the MOSFET transistor, wherein the further region with the second type of conductivity extends as far as the buried region with the first type of conductivity; a further region with the first type of conductivity and with a high concentration of impurities, which extends from the front surface of the chip into the further region with the second type of conductivity, and which comprises a source region of the MOSFET transistor; a third electrically conductive surface contact element on the further region with the first type of conductivity, with the function of a source electrode of the MOSFET transistor; a strip of electrically conductive material disposed over the channel, insulated from the front surface of the chip by a layer of insulating material, and having the function of a gate electrode of the MOSFET transistor; and an additional region with the first type of conductivity and with a high concentration of impurities, which extends from the front surface of the chip into the further region with the second type of conductivity, as far as the buried region with the first type of conductivity, defining, with the further region with the first type of conductivity, the channel of the MOSFET transistor, and comprising a drain region of the MOSFET transistor.