A 10.16% Efficiency On-Chip Solar Cells With Analytical Model Based on a Standard Bulk CMOS Process for Self-Powered Microsensors

Energy harvesting systems can power microsensors by harvesting energy from the environment. On-chip solar cells made by photodiodes serve as crucial components for highly-integrated energy harvesting systems. To maximize the vertical photoactive area and achieve on-chip solar cells with enhanced photoelectric conversion capabilities, the photoactive area is increased by segmenting the doped region. With the assistance of an approximate model, an optimized segmented triple-well photodiode design is proposed and implemented in a standard
$0.18~\mu \text{m}$
bulk CMOS process. Measurement results demonstrate a photoelectric conversion efficiency of 10.16% for the proposed segmented triple-well on-chip solar cell, which represents a 39.94% improvement compared to traditional unsegmented triple-well on-chip solar cells. The short-circuit current is 26.51% higher than that of the traditional one.