Patent ID: 7939414
Filing Date: 2011-05-10
Classification: H01L

Abstract:
1. A method comprising: forming a first isolation trench in a substrate, the first isolation trench including (i) a first side and (ii) a second side opposite the first side; forming a first photoresist layer over the substrate; patterning the first photoresist layer to reveal the substrate on the first side of the first isolation trench; performing a shallow doping of the substrate revealed on the first side of the first isolation trench with a first dopant to form a base pick-up region, the shallow doping being performed such that doping of the second side of the first isolation trench with the first dopant is substantially avoided; doping the substrate on the second side of the first isolation trench with a second dopant to form at least one emitter region, the second dopant being different from the first dopant; stripping the first photoresist layer after having doped the substrate revealed on the first side of the first isolation trench; forming a second photoresist layer over the substrate after having stripped the first photoresist layer; and patterning the second photoresist layer to reveal the substrate on the second side of the first isolation trench.