Pyroelectric thin film infrared focal plane detector chip and manufacturing method thereof

Abstract

The invention relates to the technical field of detectors, in particular to a pyroelectric thin film infrared focal plane detector chip. The pyroelectric thin film infrared focal plane detector chip sequentially comprises a substrate, a bond coat, a heat insulation supporting structure, a lower electrode, a photosensitive element, an upper electrode and an infrared absorbing layer from bottom to top. The heat insulation supporting structure comprises a thermal insulating layer and a transition supporting layer formed on the surface of the thermal insulating layer, wherein the thermal insulating layer comprises SiO2 nanometer arrays and TiO2 nanometer arrays, and the SiO2 nanometer arrays and the TiO2 nanometer arrays are alternatively stacked up and down; the transition supporting layer comprises a plurality of SiO2 transition structures and HfO2 films deposited on the surfaces of the SiO2 transition structures, the SiO2 transition structures are sequentially stacked from bottom to top, and the porosity of the transition supporting layer gradually reduces from bottom to top. The pyroelectric thin film infrared focal plane detector chip is simple in preparation method, the porosity of the heat insulation supporting structure is flexibly adjusted, thermal conductivity of the detector chip is effectively reduced, and sensitivity, stability and reliability of a detector are meanwhile improved except that stress releasing requirements for the heat insulation supporting structure of the detector are met.

Description

technical field [0001] The invention relates to the field of infrared detection technology, especially to a kind of high-efficiency and reliable SiO 2 and TiO 2 Composite material and composite structure pyroelectric infrared focal plane detector thermal insulation support structure and manufacturing method thereof. Background technique [0002] Pyroelectric thin-film infrared focal plane detector has the advantages of operating frequency at room temperature, wide spectral response, fast response speed, high detection rate, can significantly improve sensor integration, and high cost performance. It is used in infrared night vision, infrared guidance, and infrared imaging. , and the use of infrared focal plane detectors for firefighting and emergency rescue and other military and civilian fields have broad applications. The sensitivity of the pyroelectric thin film infrared focal plane detector mainly depends on the pyroelectric coefficient of the photosensitive element thi...

AI Technical Summary

Problems solved by technology

However, the preparation of this structure relies on techniques such as micromachining and sacrificial layers, and there are problems such as complex process, mismatch of thermal expansion coefficients between multilayer films in the device structure, resulting in broken electrode leads, resulting in low yield and high cost.

[0005] Especially SiO prepared by sol-gel method 2 The preparation method of airgel porous film as a thermal insulation layer requires complex and harsh process conditions, requires solvent volatilization and drying under supercritical conditions, and is affected by factors such as catalysts and side reactions of gelation reactions, so it is not suitable for controlling the formation of pore structures , affecting SiO 2 Mechanical properties and thermal conductivity reliability of airgel

This preparation method simply uses SiO 2 Airgel has obvious absorption in the 3-8μm band, which will cause SiO 2 Increased thermal conductivity of airgel

Moreover, in the process of manufacturing pyroelectric thin film infrared focal plane detector chips, repeated high-temperature annealing treatments are required, resulting in pure SiO 2 As the number of annealing increases, the porosity of airgel becomes lower and lower, and the ideal thermal insulation effect cannot be achieved, resulting in a decrease in detector sensitivity

Although in SiO 2 Airgel doped with TiO 2 Or carbon black and other infrared blocking agents, can significantly improve SiO 2 The thermal insulation efficiency of airgel at high temperature, but the doping method and process also have various difficulties, and it is difficult to operate and control

In addition, the high porosity of SiO 2 When aerogel is used as a thermal insulation structure, the surface roughness is too high, which may easily cause the detector to break down due to local high current

[0006] In summary, due to the above-mentioned limitations in the preparation process and technology, the preparation of the thermal insulation layer has become a key technical bottleneck in the production process of the pyroelectric thin film infrared focal plane detector chip

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