Patent ID: 7696596

Claim:
A CMOS image sensor having a bipolar junction transistor, comprising: a first photodiode of a first conductivity, a first collector area of the first conductivity, and a first emitter area of the first conductivity formed over a conductive substrate; a first epi-layer having a first plug of the first conductivity connected to the first photodiode, a second collector area connected to the first collector area, and a second emitter area connected to the first emitter area; a second photodiode of the first conductivity formed by implanting ions in the first epi-layer, and a third collector area connected to the second collector area, and a third emitter area connected to the second emitter area in the first epi-layer; a second epi-layer over the first epi-layer and having a second plug of the first conductivity connected to the second photodiode, a fourth emitter area connected to the third emitter area, and a fourth collector area connected to the third collector area; a third photodiode of the first conductivity, an emitter contact area of the first conductivity connected to the fourth emitter area, and a collector contact area of the first conductivity connected to the fourth collector area formed on the second epi-layer; and a base contact area of a second conductivity formed over the second epi-layer.