Methods of forming insulated gate bipolar transistors having built-in freewheeling diodes and transistors formed thereby

A method of forming an insulated-gate bipolar transistor having a built-in freewheeling diode, comprising the steps of:

• forming a cathode region of first conductivity type containing a first array of emitter regions of second conductivity type therein, extending to a face thereof;
• then
• forming a base region of first conductivity type on the face of the cathode layer;
• then
• forming a second array of regions of second conductivity type in the base region at a face thereof, so that a first plurality of the regions in the second array extend opposite respective emitter regions in the first array, but a second plurality of the regions in the second array do not extend opposite respective emitter regions in the first array;
• then
• forming at least one source region in each of the first plurality of regions in the second array, but not in the second plurality of regions in the second array;
• and
• forming insulated gate electrode means on the face of the base region for electrically connecting the source regions to the base region in response to application of a predetermined forward gate bias thereto;
• forming a first electrode in ohmic contact with the second array of regions of second conductivity type;
• and
• forming a second electrode in ohmic contact with the first array of emitter regions and the cathode layer.

A method of forming an insulated gate bipolar transistor having a diode, comprising the steps of:

• forming a plurality of emitter regions of second conductivity type by selectively implanting impurity ions of second conductivity type into a semiconductor substrate of first conductivity type;
• forming an epitaxial layer of first conductivity type on the semiconductor substrate;
• forming a plurality of collector regions of second conductivity type and a plurality of anode regions of second conductivity type by selectively implanting impurity ions of second conductivity type into the epitaxial layer so that the plurality of collector regions extend opposite the plurality of emitter regions;
• forming a plurality of source regions in the plurality of collector regions;
• and
• polishing a surface of the semiconductor substrate of first conductivity type to expose the plurality of emitter regions of second conductivity type.

A method of forming an integrated power semiconductor device containing insulated gate bipolar transistor cells and freewheeling diode cells therein, comprising the steps of:

• forming a semiconductor substrate of first conductivity type containing an array of emitter regions of second conductivity type adjacent a first face thereof;
• forming an array of collector regions of second conductivity type in the substrate, adjacent a second face thereof;
• forming an array of anode regions of second conductivity type in the substrate, adjacent the second face thereof;
• forming at least one source region of first conductivity type in each of the collector regions;
• forming insulated gate electrode means, on the second face, for electrically connecting a plurality of the source regions to the substrate by inversion layer channels in respective ones of the collector regions, in response to application of a forward gate bias, and for electrically connecting a plurality of the collector regions to a plurality of the anode regions by inversion layer channels in the substrate, in response to application of a reverse gate bias;
• forming a first electrode electrically connected to the array of collector regions and the array of anode regions, adjacent the second face;
• and
• forming a second electrode electrically connected to the array of emitter regions and the substrate, adjacent the first face.