Three‑dimensional integration of complementary metal oxide semiconductors for photodetection of Silicon heterojunctions

With the increasing demand for high-resolution and high-bandwidth photodetection, traditional planar integrated detectors have gradually exposed their limitations in terms of signaling delay, interconnect density and power consumption. In order to meet the demand for high-speed and low-noise photodetection, a three-dimensional heterogeneous integrated array based on silicon-based graphene photodetectors with wafer-level copper-filled silicon vias is proposed to realize high-density vertical interconnections and low-loss signal transmission. The device is constructed on a 4-inch high-resistance silicon substrate with high aspect ratio wafer-level silicon through-hole channels and integrated with low-noise complementary metal oxide semiconductor circuits. Test results show a single-image-element responsivity of 0.62 A/W at 532 nm and -2 V, an external quantum efficiency of 144.8%, and a dark current of <0.38 nA; a bandwidth of 3 MHz at an integration time of 0.5 μs, a rise/fall time of 0.15 μs, and an overshoot of <3%. The comparison of noise and imaging performance shows that the research method has the lowest equivalent noise power of 3.41pW/Hz, which is better than other advanced 3Dintegrationschemes. It can be seen that the research method has obvious advantages in high-speed imaging and broad-spectrum detection, which can provide feasible solutions and technical support for the development of high-sensitivity optoelectronic sensing, chip-scale optical interconnects, and new-generation optoelectronic imaging systems.