Phototransistor image sensor in silicon on sapphire

We present a back-illuminated 32 x 32 pixel image sensor in 0.5-mum silicon-on-sapphire process. The imager performs "snap-shot" image acquisition and analog readout at a continuous rate of thousands of frames/s and consumes as little as 250 muW. Each pixel consists of a phototransistor and a memory capacitor in 40 mum x 40 mum with a fill factor of 43%. The image sensor is suited for hyper-spectral imaging at high speeds.