Darlington pair bipolar junction transistor sensor

A Darlington pair sensor is disclosed. The Darlington pair sensor has an amplifying/horizontal bipolar junction transistor (BJT) and a sensing/vertical BJT and can be used as a biosensor.The amplifying bipolar junction transistor (BJT) is horizontally disposed on a substrate. The amplifying BJT has a horizontal emitter, a horizontal base, a horizontal collector, and a common extrinsic base/collector. The common extrinsic base/collector is an extrinsic base for the amplifying BJT.The sensing BJT has a vertical orientation with respect to the amplifying BJT. The sensing BJT has a vertical emitter, a vertical base, an extrinsic vertical base, and the common extrinsic base/collector (in common with the amplifying BJT). The common extrinsic base/collector acts as the sensing BJT collector. The extrinsic vertical base is separated into a left extrinsic vertical base and a right extrinsic vertical base giving the sensing BJT has two separated (dual) bases, a sensing base and a control base.The Darlington pair sensor has high in-situ signal amplification with low noise and uses substrate space effectively.