An active pixel sensor (APS) based on high gain CMOS compatible lateral bipolar transistor (LBT) on SOS substrate with backside illumination

In this paper, an innovative Active Pixel Sensor based on high gain CMOS compatible Lateral Bipolar Transistor (LBT) on Silicon-on-Sapphire (SOS) substrate has been introduced. A number of unique features are presented in the new design to overcome the difficulties to fabricate high performance APS in SOI related technology, including: (1) PMOSFET reset transistor to increase pixel voltage swing without area penalty; (2) a LBT as charge sensing element to increase responsivity; and (3) backside illumination through the transparent sapphire substrate to improve optical transmission. The APS has been implemented in a Peregrine's 0.5 μm SOS CMOS process and verified to work at a low power supply voltage of 1.2 V.