A CMOS Sensor based on Single Photon Avalanche Diode for Distance Measurement Applications

This paper describes the design of a 64x2-pixel array, fabricated in a conventional industrial high-voltage 0.8um CMOS technology, and aimed at three dimensional measurements based on the Time-Of-Flight technique. Light signals are detected using a photodiode biased above its breakdown voltage so that an extremely high sensitivity can be achieved exploiting the intrinsic multiplication effect of the avalanche phenomenon. A single photon avalanche diode and dedicated read-out electronics for light pulses arrival-time estimation have been implemented in a 38x180-um2 pixel with an expected power consumption of about 20 uW. To increase the distance measurement resolution a multiple pulse measurement is used, extracting the mean value of the light pulse arrival-time directly in each pixel; this innovative approach dramatically reduces the dead-time of the pixel read-out, allowing a high frame rate imaging to be achieved