Reverse bipolar junction transistor integrated circuit
View Patent ↗A Reverse Bipolar Junction Transistor (RBJT) integrated circuit comprises a bipolar transistor and a parallel-connected distributed diode, where the base region is connected neither to the collector electrode nor to the emitter electrode. The bipolar transistor has unusually high emitter-to-base and emitter-to-collector reverse breakdown voltages. In the case of a PNP-type RBJT, an N base region extends into a P− epitaxial layer, and a plurality of P++ collector regions extend into the base region. Each collector region is annular, and rings a corresponding diode cathode region. Parts of the epitaxial layer serve as the emitter, and other parts serve as the diode anode. Insulation features separate metal of the collector electrode from the base region, and from P− type silicon of the epitaxial layer, so that the diode cathode is separated from the base region. This separation prevents base current leakage and reduces power dissipation during steady state on operation.
1. An integrated circuit comprising:
a first metal electrode;
a second metal electrode;
a third metal electrode;
a bipolar transistor, wherein a base of the bipolar transistor is coupled to the second metal electrode, wherein the base is separated from the first metal electrode by a plurality of insulation features, wherein the bipolar transistor has an emitter-to-base reverse breakdown voltage of at least 156 volts, and wherein the bipolar transistor has an emitter-to-collector reverse breakdown voltage of at least 156 volts; and
a distributed parallel diode, wherein a first electrode of the distributed parallel diode is coupled to a collector of the bipolar transistor and is also coupled to the first metal electrode, wherein a second electrode of the distributed parallel diode is coupled through substrate material to an emitter of the bipolar transistor and is also coupled to the third metal electrode, wherein the collector of the bipolar transistor extends into and is surrounded by the base, and wherein the first electrode of the distributed parallel diode is separated from the base by the insulation features.
2. The integrated circuit of claim 1 , wherein the bipolar transistor is a PNP transistor, and wherein the first electrode of the distributed parallel diode is a plurality of cathode diffusion regions.
3. The integrated circuit of claim 1 , wherein the bipolar transistor is an NPN transistor, and wherein the first electrode of the distributed parallel diode is a plurality of anode diffusion regions.
4. The integrated circuit of claim 1 , wherein the base is in contact with the insulation features, and wherein the first metal electrode is in contact with the insulation features.
5. The integrated circuit of claim 1 , wherein the base is electrically insulated from the first metal electrode by the insulation features.
6. The integrated circuit of claim 1 , wherein the insulation layer forms a plurality of washer-shaped annular features of insulation.
7. The integrated circuit of claim 6 , wherein the first metal electrode is separated from the base by the plurality of washer-shaped annular features of insulation.
8. The integrated circuit of claim 1 , wherein the collector of the bipolar transistor extends into the base by 0.5 microns.
9. The integrated circuit of claim 1 , wherein the base of the bipolar transistor extends under the collector of the bipolar transistor from an upper semiconductor surface 2.8 microns into the emitter of the bipolar transistor.
10. The integrated circuit of claim 1 , wherein the collector of the bipolar transistor has a rectangular annular shape when considered from a top-down perspective.
11. The integrated circuit of claim 1 , wherein the first electrode of the distributed parallel diode extends from an upper semiconductor surface four microns into the emitter of the bipolar transistor.
12. The integrated circuit of claim 1 , wherein the first electrode of the distributed parallel diode extends from an upper semiconductor surface down into the emitter of the bipolar transistor a greater distance than the base of the bipolar transistor extends under the collector of the bipolar transistor down from the upper semiconductor surface into the emitter of the bipolar transistor.
13. An integrated circuit comprising:
a first metal electrode;
a second metal electrode;
a third metal electrode;
a bipolar transistor, wherein a collector of the bipolar transistor is coupled to the first metal electrode, wherein a base of the bipolar transistor is coupled to the second metal electrode, wherein an emitter of the bipolar transistor is coupled to the third metal electrode, wherein the bipolar transistor has an emitter-to-base reverse breakdown voltage of at least 156 volts, and wherein the bipolar transistor has an emitter-to-collector reverse breakdown voltage of at least 156 volts;
means for insulating the first metal electrode from the base and from the emitter of the bipolar transistor; and
a distributed parallel diode, wherein a first electrode of the distributed parallel diode is coupled to the first metal electrode, wherein a second electrode of the distributed parallel diode is coupled via wafer material to the third metal electrode, wherein the collector of the bipolar transistor extends into and is surrounded by the base, and wherein the first electrode of the distributed parallel diode is separated from the base by the means.
14. The integrated circuit of claim 13 , wherein the integrated circuit comprises a silicon layer, and wherein the means for insulating is disposed on a surface of the silicon layer.
15. The integrated circuit of claim 14 , wherein the means for insulating comprises a plurality of washer-shaped annular features of insulation.
16. The integrated circuit of claim 13 , wherein the means for insulating is at least one micron thick.
17. The integrated circuit of claim 13 , wherein the collector of the bipolar transistor extends 0.5 microns into the base of the bipolar transistor.
18. The integrated circuit of claim 13 , wherein the base of the bipolar transistor extends under the collector of the bipolar transistor from an upper semiconductor surface 2.8 microns into the emitter of the bipolar transistor.
19. The integrated circuit of claim 13 , wherein the first electrode of the distributed parallel diode extends from an upper semiconductor surface down into the emitter of the bipolar transistor a greater distance than the base of the bipolar transistor extends under the collector of the bipolar transistor down from the upper semiconductor surface into the emitter of the bipolar transistor.
20. An integrated circuit comprising:
a first metal electrode;
a second metal electrode;
a third metal electrode;
a bipolar transistor, wherein a base of the bipolar transistor is coupled to the second metal electrode, wherein the bipolar transistor has an emitter-to-base reverse breakdown voltage of at least 156 volts, and wherein the bipolar transistor has an emitter-to-collector reverse breakdown voltage of at least 156 volts; and
a distributed parallel diode, wherein a first electrode of the distributed parallel diode is coupled to a collector of the bipolar transistor and is also coupled to the first metal electrode, wherein a second electrode of the distributed parallel diode is coupled via substrate wafer material to an emitter of the bipolar transistor and is also coupled to the third metal electrode, and wherein the collector of the bipolar transistor extends into and is surrounded by the base, and the first metal electrode is electrically isolated from the base.