Patent ID: 7491605

Claim:
A method for making a semiconductor structure of a memory device, comprising: forming a first dopant region of a second conductivity type in a substrate of a first conductivity type; forming a bipolar transistor, including forming a base region of the bipolar transistor, the base region being of the first conductivity type; forming a second dopant region of the first conductivity type in the first dopant region, the second dopant region being more heavily doped than the first dopant region, the second dopant region being distinct and separate from the base region, said forming a second dopant region and said forming a base region of the bipolar transistor occur in a same step; forming a gate dielectric atop the second dopant region; forming a first gate conductor atop the gate dielectric; forming a field-effect transistor, comprising forming a second gate conductor coupled to the first gate conductor; wherein the second dopant region, the gate dielectric, and the first gate conductor form a capacitor.