Integrated Solar Energy Harvesting and Storage

To explore integrated solar energy harvesting as a power source for low power systems, an array of energy scavenging photodiodes based on a passive-pixel architecture for CMOS imagers has been fabricated together with storage capacitors implemented using on-chip interconnect in a 0.35-mum bulk process. Integrated vertical plate capacitors enable dense energy storage without limiting optical efficiency. Tests were conducted with both a white light source and a green laser. Measurements indicate that 225 muW/mm² output power may be generated by white light with an intensity of 20 kLUX.