Patent ID: 8258545

Claim:
An integrated circuit comprising: a substrate; and a bipolar transistor disposed over the substrate, the bipolar transistor comprising: a base electrode disposed around at least one germanium-containing layer; an emitter electrode disposed over the at least one germanium-containing layer; and at least one isolation structure disposed between the emitter electrode and the at least one germanium-containing layer, a top surface of the at least one isolation structure being disposed between and electrically isolating a top surface of the emitter electrode from a top surface of the at least one germanium-containing layer, wherein the at least one isolation structure includes: a first dielectric layer disposed adjacent to a sidewall of the emitter electrode; and a second dielectric layer disposed adjacent to the first dielectric layer and in direct contact with the emitter electrode, wherein the second dielectric layer and the first dielectric layer have different etch selectivity.