Wenbin Zhou

Imaging sensing based on silicon optoelectronic chips faces significant challenges in extending the detection range to the near-infrared (NIR) band. In this paper, we demonstrate near-infrared CoSi2/Si Schottky diodes as photodetectors in the CMOS process. To enhance photoabsorption and broaden the spectral range for detection, the CoSi2/Si Schottky diode is integrated with a fishbone-shaped Al/W/CoSi2 multilayer structure, which provides a strong surface plasmon resonance (SPR) effect. Experimental results show that, under a bias voltage of −1 V and NIR irradiation, the device enables a maximum responsivity of 1.7 mA/W @ 1550 nm and 0.1 mA/W @ 2000 nm. The rise and fall times for a 1550 nm pulse source are 16.3 and 15.8 ms, respectively. Both photoelectric and photothermal responses are observed in photodetectors, with the photothermal effect contributing more significantly at longer wavelengths. The mechanisms of these two effects and the optimization directions for long-wavelength detection are discussed. This work overcomes the spectral limitations of conventional CMOS imaging sensors, providing a low-cost, scalable solution for high-performance NIR imaging applications.

Multi-spectral imaging enhances the information diversity of the object with complex, expensive, and low integrated components. Here, we demonstrated an antenna-coupled microbolometric detector in complementary metal-oxide-semiconductor (CMOS) technology, utilizing SiO2 absorption and L-shaped fractal antenna to achieve multi-band detection from infrared (IR) to terahertz (THz). Experimental results demonstrate that the detector can achieve high sensitivity detection in both THz and IR bands, with the maximum detectivity of 5 (10⁸ cm·Hz^1/2/W @305 GHz and 7 (10⁸ cm·Hz^1/2/W @8.55 µm, respectively. The presented multi-spectral detector is easily implementable in integrated circuit process, conducive to high-density, low-cost, and high-performance array imaging.

Fe contamination has always been one of the most critical issues in the integrated circuit (IC) industry due to its catastrophic effect on device reliability and electrical characteristics. With complementary metal oxide semiconductor (CMOS) technology scaling down, this issue has been attracting more attention. In this paper, the impact of Fe impurity on the reliability of gate oxide integrity (GOI) in advanced CMOS technology is investigated. Intentional contamination of polysilicon gates was conducted in both boron- and phosphorus-doped devices. Failure analysis of the gate oxide was conducted with high-resolution transmission electron microscopy (HRTEM) and the energy dispersive X-ray (EDX) technique. The experimental results disclose that the properties of PMOS are much more sensitive to Fe contamination than those of NMOS. It is suggested that the reason for the above phenomena is that Fe precipitates at the PMOS gate/oxide interface but dissolves uniformly in the NMOS poly gate due to lower formation energy of the FeB pair (0.65 eV) in PMOS than that of the P4-Fe cluster (3.2 eV) in NMOS.

The growing need for the multiband photodetection of a single scene has promoted the development of both multispectral coupling and broadband detection technologies. Photodetectors operating across the infrared (IR) to terahertz (THz) regions have many applications such as in optical communications, sensing imaging, material identification, and biomedical detection. In this review, we present a comprehensive overview of the latest advances in broadband photodetectors operating in the infrared to terahertz range, highlighting their classification, operating principles, and performance characteristics. We discuss the challenges faced in achieving broadband detection and summarize various strategies employed to extend the spectral response of photodetectors. Lastly, we conclude by outlining future research directions in the field of broadband photodetection, including the utilization of novel materials, artificial microstructure, and integration schemes to overcome current limitations. These innovative methodologies have the potential to achieve high-performance, ultra-broadband photodetectors.