The metal-type microbolometers in CMOS technology normally suffer low resistivity and high thermal conductivity, limiting their performance and application areas. In this paper, we demonstrate a polysilicon microbolometer fabricated in 0.18 µm CMOS and post-CMOS processes. The detector is composed of a SiO₂ absorber coupled with a salicided poly-Si thermistor that has a high resistivity of 1.37×10⁻⁴ Ω·cm and low thermal conductivity of 18 W/m·K. It is experimentally shown that the microbolometer with a 40 µm × 40 µm pixel size has a maximum responsibility and detectivity of 2.13×10⁴ V/W and 2.33×10⁹ cmHz^1/2/W, respectively. The results are superior to the reported metal-type and diode-type microbolometers in the CMOS process and provide good potential for a low-cost, high-performance, uncooled microbolometer array for infrared imaging applications.

The resistive microbolometer fabricated by using CMOS technology can be monolithically integrated with the readout circuit but usually performs poorly in responsivity and detectivity. In this paper, the salicide poly-Si microbolometer with Al grating structure is demonstrated in the standard CMOS process. The simulation results show that not only are surface plasmon polaritons generated at the interface of the Al grating and SiO ₂ , Al grating also provides the infrared resonant cavity required for the absorber, which improves the responsivity of the microbolometer. According to the experimental results, the maximum detectivity of the microbolometer with the grating structure reaches up to 2.26 × 10 ⁹ cmHz ^1/2 /W at 10 μm, which means an increase by 27.8% compared to the one without the Al grating. Moreover, the average detectivity of the microbolometer is also improved when the wavelength ranges from 7 μm to 13 μm. It is effortless to implement the proposed high-performance microbolometer in a unit structure based on CMOS technology, which is favorable to high-density array integration.

Microbolometers based on the CMOS process has the important advantage of being automatically merged with circuits in the fabrication of larger arrays, but they typically suffer from low detectivity due to the difficulty in realizing high-sensitivity thermistors in the CMOS process. In this paper, two resistive microbolometers based on polysilicon and metal Al thermistors, respectively, are designed and fabricated by the standard CMOS process. Experimental results show that the detectivity of the two resistive microbolometers can reach a maximum of 1.78 × 10⁹ cmHz^1/2/W at 25 μA and a maximum of 6.2 × 10⁸ cmHz^1/2/W at 267 μA. The polysilicon microbolometer exhibits better detectivity at lower bias current due to its lower effective thermal conductivity and larger resistance. Even though the thermal time constant of the polysilicon thermistor is three times slower than that of the metal Al thermistor, the former is more suitable for designing a thermal imaging system with sensitive and low power consumption.

The suppression of the crosstalk in a CMOS THz detector is essential for enhancing the performance of detector arrays; however, it presents several technical challenges at the chip level. In this paper, a novel structure featuring a mushroom-like artificial magnetic conductor (M-AMC) is developed to suppress the crosstalk between CMOS THz detectors with on-chip antennas. Three-dimensional simulation results show that the M-AMC structure, which is designed by metal Al and doped-Si materials in the CMOS process, not only reduces the transmission coefficient of the electromagnetic wave between adjacent pixels but also enhances the electric field of the target pixels. A 0.65 THz detector array with a M-AMC structure based on the on-chip antenna was fabricated. Experimental results present that after implanting the M-AMC structure, the noise equivalent power (NEP) at the central frequency of pixels significantly decreases by 315.5%. Moreover, the distribution of NEP becomes more uniform, as evidenced by a reduction in the standard deviation coefficient of 26.3%. This demonstrates the effectiveness of the method in suppressing crosstalk and improving the responsivity of CMOS THz detectors, which can be used for high-performance THz detector arrays.