CN-122002933-A - High-performance infrared focal plane detector based on super-structure lens effect

Abstract

The invention discloses a high-performance infrared focal plane detector based on a super-structure lens effect, and belongs to the technical field of photoelectric detection. The invention aims at providing a novel detector architecture for integrally and cooperatively designing metal microcavity resonance and super-structure lens condensation effect at a pixel level. The periodically arranged detector pixels have the dual functions of microcavity resonance frequency selection and microlens wavefront regulation simultaneously by carrying out multi-physical field cooperative optimization on quantum well materials, metal microcavity structures and array periods. On one hand, incident infrared light is converged through the ultra-structure lens effect induced by the array period to enhance the energy density of the light field, and on the other hand, the incident light coupled into the metal microcavity can excite a resonance mode in the microcavity to further locally enhance the light field of the active region. The invention does not need an external optical element, the process is completely compatible with the existing focal plane technology, and a brand new technical approach is provided for high-performance narrow-band infrared detection.

Inventors

• ZHEN HONGLOU
• ZHANG CHENG
• LU WEI
• LUO JIEXING
• Niu yilin
• LIU SIWEN
• Hai Xinyi
• YI RUI
• MEI YONGFENG

Assignees

• 中国科学院上海技术物理研究所

Dates

Publication Date

20260508

Application Date

20260209

Claims (10)

1. 1. A high-performance infrared focal plane detector based on a super-structure lens effect is characterized by comprising a periodically arranged metal microcavity pixel array, wherein each single metal microcavity pixel is of a mesa-type metal microcavity structure and comprises a substrate, a lower electrode layer, a quantum well infrared light absorbing layer and an upper electrode layer from bottom to top, The side wall and the upper surface of the mesa-type metal microcavity structure are sequentially covered with an insulating dielectric film and a continuous metal film, and the metal film and the lower electrode layer jointly form a three-dimensional metal microcavity wrapping the quantum well infrared light absorbing layer; the periodically arranged metal microcavity pixel array macroscopically induces a super-structure lens effect, incident infrared light wave fronts are converged to microcavity regions of pixels to realize condensation enhancement, ohmic contact electrodes are respectively prepared on the surfaces of the upper electrode layer and the lower electrode layer, and the ohmic contact electrodes are interconnected with a reading circuit through windowing on an insulating dielectric film.
2. 2. The ultra-structured lens effect-based high performance infrared focal plane detector of claim 1, wherein the metal film is used only as an optical reflecting wall constituting the three-dimensional metal microcavity and a structure for adjusting the wavefront phase to induce the ultra-structured lens effect, and is not used as an electrical electrode.
3. 3. The ultra-structured lens effect based high performance infrared focal plane detector of claim 1, wherein the insulating dielectric film is used for electrically isolating the metal thin film from the quantum well infrared light absorbing layer, the upper electrode layer and the lower electrode layer.
4. 4. The ultra-structured lens effect-based high performance infrared focal plane detector of claim 1, wherein the mesa-type metal microcavity structure is a cylindrical mesa having a plurality of circular grooves arranged periodically on its top surface.
5. 5. The ultra-structured lens effect-based high-performance infrared focal plane detector according to claim 1, wherein the mesa-type metal microcavity structure is a square column mesa, and the top surface of the mesa-type metal microcavity structure is provided with a plurality of square grooves which are periodically arranged.
6. 6. The ultra-structured lens effect based high performance infrared focal plane detector of claim 1, wherein the arrangement period of the array of metal microcavity pixels is associated with a target detection wavelength, configured to match the concentration peak of the ultra-structured lens effect to the resonant wavelength of the three-dimensional metal microcavity at the target wavelength.
7. 7. The high-performance infrared focal plane detector based on the super-structured lens effect as claimed in claim 1, wherein the quantum well infrared light absorbing layer is of a GaAs/AlGaAs quantum well material structure.
8. 8. The ultra-structured lens effect based high performance infrared focal plane detector of claim 1, wherein the quantum well infrared light absorbing layer has a lower doping concentration than conventional quantum well infrared detectors.
9. 9. The ultra-structured lens effect based high performance infrared focal plane detector of claim 1, wherein the ohmic contact electrode is interconnected with the readout circuitry by flip-chip bonding via indium columns vapor deposited on the dielectric film window.
10. 10. The high-performance infrared focal plane detector based on the super-structure lens effect as claimed in claim 1, wherein the quantum well infrared light absorbing layer is of a multi-layer periodic structure, and the peak wavelength of the intrinsic absorption spectrum is matched with the resonance wavelength of the three-dimensional metal microcavity and the condensing wavelength of the super-structure lens effect in design and is located at the same target detection wavelength.

Description

High-performance infrared focal plane detector based on super-structure lens effect Technical Field The invention belongs to the technical field of photoelectric detection, and particularly relates to a high-performance infrared focal plane detector based on a super-structure lens effect. Background Any object can radiate infrared light to the environment, and the radiation intensity of the infrared light is closely related to the temperature, material characteristics and surface state of the object, so that the infrared detection base is formed. Infrared imaging detection is a non-contact sensing technology, and has important application in the fields of industrial detection, medical diagnosis, environmental monitoring and the like by capturing infrared light radiated by an object and converting the infrared light into a visual image. The combination of infrared detection and a narrow-band technology is a key for realizing high-sensitivity and high-specificity target identification. The mainstream narrowband detection scheme is to add a narrowband filter or a beam-splitting grating in front of a detector with broad spectral response (such as an HgCdTe detector). The quantum well infrared detector (QWIP) has a narrower intrinsic response bandwidth due to a sub-band transition mechanism, and has advantages in the fields of narrow-band gas detection and the like. However, the quantum efficiency of qwi intersubband transitions is generally low, severely limiting its detection performance. In order to improve the optical coupling and absorption efficiency of quantum well detectors, the prior art is mainly divided into two categories. One is to integrate optical structures such as micro lenses in front of or on the surface of the detector, and increase the incident luminous flux through geometrical condensation. The scheme is an external optical element essentially, has high integration difficulty, complex process and single function, and can only improve the luminous flux but can not realize spectrum selection. Another class is metal-insulator-metal (MIM) microcavity structures that exploit microcavity resonance effects to enhance light absorption, such as based on plasmon effects. The structure forms the Fabry-Perot resonance through near field coupling between the upper metal layer and the lower metal layer, and the response rate of specific wavelength can be remarkably improved. However, the structure has serious metal ohmic loss, the absorption efficiency is difficult to break through the intrinsic limit (usually lower than 20%), the resonance bandwidth is wider, and the narrow-band filtering performance is limited. In recent years, the adoption of a medium microcavity to realize frequency selection is studied, and the efficiency can reach about 80% although the metal absorption is reduced, but the active light-gathering capability is still not provided, and the efficiency is still a bottleneck. In summary, in the prior art, the two functions of light condensation enhancement and resonance frequency selection are generally independent of each other and are realized through different elements or structures, so that it is difficult to integrate on the pixel scale. The technical problem to be solved in the field is how to greatly break through the theoretical upper limit of quantum efficiency and realize complete compatibility with the focal plane process while maintaining the narrow-band response characteristic. Disclosure of Invention In order to solve the technical problems, the invention provides the high-performance infrared focal plane detector based on the super-structure lens effect, the detection pixels are designed into a microcavity structure, and the detector naturally has the light condensing effect of the micro-lens and the narrow-band detection function by utilizing the superposition of the specific periodic arrangement of the pixels and the resonance enhancement effect of the active region of the microcavity structure, so that the quantum efficiency bottleneck of the quantum well device is broken through greatly. In addition, due to the pixel structure with focal plane dimension, compared with a super-surface structure requiring an additional customized process, the detector provided by the invention not only has super-high absorption quantum efficiency obtained by micro-lens condensation, but also can conveniently realize the development of a large area array focal plane chip by a device structure compatible with the focal plane process, and has important application value in the aspects of high-sensitivity infrared imaging and the like. In order to achieve the above purpose, the invention adopts the following technical scheme: A high-performance infrared focal plane detector based on super-structure lens effect comprises a periodically arranged metal microcavity pixel array, wherein each metal microcavity pixel is of a mesa-type metal microcavity structure and comprises a substrate, a lower e