. "The HBT structure further comprises a second conductivity type mono-crystalline base layer (e.g., a base layer doped with a p-type dopant, such as boron (B)) adjacent to a first side of the emitter layer (e.g., below the emitter layer) and a first conductivity type polysilicon electrode (e.g., a polysilicon electrode doped with an n-type dopant) that is adjacent to a second side of the emitter lay" . . .