On-chip solar battery structure for CMOS LSI

Abstract

A built-in method of on-chip solar battery in a CMOS LSI is proposed. The proposed solar battery can be formed using conventional CMOS process technology. It can generate a high voltage of 0.6-0.83V by a series connection structure of two types of p-n junction diodes formed with the CMOS circuit simultaneously on the LSI chip. The generated voltage is sufficient to drive the conventional CMOS circuit without modification. The test chip was produced experimentally using conventional 0.35µm CMOS technology, and the drive performance of the on-chip solar battery was evaluated. The conversion efficiency of the proposed solar battery was 2.6%. The area of the solar battery required for power consumption was 6.1mm²/µW in the case of the 2000lx illumination.