Optically Powered Energy Source in a Standard CMOS Process for Integration in Smart Dust Applications

In order to miniaturize nano-power sensor nodes or smart dust, an optically powered energy source is developed to replace traditional batteries or solar cells. This energy source consists of two photodiodes, which are P-well/DN-well and N-well/P-sub. The two photodiodes with an area of 1.5mm²were fabricated using the UMC0.25μm CMOS process and tested using an 830nm laser. Measurement results show that the energy source is able to generate a voltage from 0.5V to 0.8V with a 3.5% conversion efficiency. The proposed energy source was made using a standard CMOS process and therefore can to be integrated with the smart dust circuit on a single chip.