All-digital, CMOS-based Photodiode Camera

CCDs (Charge-Coupled Devices), and more recently, CMOS (complementary-symmetry metal-oxide-semiconductor) APS (Active Pixel Sensor) cameras have revolutionized imaging instrumentation and the many fields that utilize these instruments. Both of these technologies rely on detecting, or integrating, the analog photo-current generated in each pixel, which limits their sensitivity and bandwidth. Counting individual optical photons with a Geiger detector provides the greatest sensitivity, and represents a true digital imaging approach that facilitates signal processing at the pixel level.This program develops a fully integrated, digital camera chip, which is an application specific integrated circuit (ASIC), that counts individual optical photons using Geiger avalanche photodiodes. This all-digital, CMOS imaging technology fulfills the demanding requirements for providing high-resolution images at GHz speeds char-acteristic of CMOS processing architectures. In Phase I, we will explore appropriate fabrication architectures for the ASIC and fabricate prototype pixel elements, along with the critical circuit components needed to support the pixel element. We will test the prototype devices and compare their measured performance to the initial design specifica-tions.