On-Chip Power Source Using Optimized On-Chip Solar Cells Based on a Standard Bulk CMOS Process for Single-Chip Self-Powered Smart Microsensors

Abstract

Enhancing the photoelectric conversion efficiency of on-chip solar cells is important for the realization of self-powered smart microsensors. The surface electrode models for the on-chip solar cell based on CMOS process is constructed. It is verified by simulations and measurements that square ring electrode (RE) and center electrode (CE) don’t cause significant differences in the internal resistance of solar cells. Adopting the CEs instead of the REs can significantly reduce the shadowing effect of surface electrodes. To solve the problem of light blockage caused by the metal interconnections in the segmented solar cells, highly doped regions are used to replace some of the metal interconnections. A 0.01mm2 segmented triple-well on-chip solar cells with the CEs and highly doped region as interconnection is fabricated using a standard 0.18 μm CMOS process. Measurement results show a 25.79% photoelectric conversion efficiency under solar simulator illuminations and has a 17.49% improvement compared to the conventional design. Utilizing the proposed solar cells, an on-chip energy harvesting power source has been realized, achieving a maximum conversion efficiency of 10.20% from incident solar power to voltage output power. Despite variations in illumination and load, this power source is able to maintain a relatively stable output voltage of 1 V.

Jingjing Liu

Associate Professor

My research interests include low-power smart micro-sensor integrated circuit design, image sensors, biomedical sensors, and energy harvesting circuits.

Jian Guan

PhD Student

My research interests include the design of solar cells and energy harvesting circuits.

Wenji Mo

Master’s Student

My research interests include circuit design of low-power RISC-V processors and self-powered SoCs.

Bingjun Xiong

PhD Student

My research interests include circuit design of optical receivers and references.

Kangkang Sun

PhD Student

My research interests include circuit design of analog to digital converter for biomedical applications and SAR ADC.

Feng Yan

PhD Student

My research interests include circuit design of analog front end for biomedical applications and sensor interfaces.

Zhipeng Li

PhD Student

My research interests include circuit design of image sensors and energy harvesting circuits.