Bipolar transistor operating method with base charge controlled by back gate bias

A method of operating a bipolar transistor that includes an emitter region, a collector region spaced laterally from the emitter region, and a base region that underlies the emitter region and extends between the emitter and collector regions with a boundary between the base and collector regions that is laterally offset from the emitter region, comprising:

• applying operating signals to said emitter, collector and base regions to establish a base-collector depletion region, and an emitter-collector current flow, and
• applying, through a nonconductive substrate which directly underlies both said base and collector regions, a back gate bias voltage to the underside of said base region of a polarity and magnitude to repel base dopant, establish an inversion layer in the base region adjacent its underside which effectively functions as an extension of the collector region, and establish a depletion region in the base region as a continuation of said base-collector depletion region immediately above said inversion layer, so that the transistor's emitter-collector current flows through said continuation of the base-collector depletion region and through said inversion layer and is substantially independent of the transistor's collector-base voltage over a substantial collector-base voltage operating range.