背照式CMOS光伏器件中近红外光反射与屏蔽结构的研究

In this brief, we investigate backside-illuminated (BSI) photovoltaic (PV) cells that can be fabricated in a standard complementary metal–oxide–semiconductor (CMOS) process to enhance energy conversion efficiency and to facilitate dense integration of the PV cells with on-chip power conversion circuitry. Particularly, to increase near-infrared (NIR) path length in the PV cells and to facilitate vertical integration of metal–insulator–metal (MIM) capacitors on top of the PV cells, polysilicon (P-Si) and metal layers in a standard CMOS process have been used as an NIR reflector and shield. As a proof of concept, multiple silicon p-n junction-based PV cells with a P-Si grating and metal grating/shielding layers for NIR reflection and a few basic CMOS power conversion circuits, such as a switched-capacitor dc–dc boost converter, an analog reference, and a voltage-controlled oscillator (VCO) have been implemented using a 180-nm standard 1P6M CMOS process, and their performance was characterized. Among the implemented PV cells, the one with a P-Si grating and a metal shield ( M_2 ) shows a 67% increase of 980-nm NIR-induced current density, and the dc–dc converter powered by the PV cells with the MIM capacitor on top of the PV cells exhibits the designed conversion ratio of 1:3.