Vanadium oxide thin film for microbolometer and preparation method thereof

Abstract

The invention discloses a method for preparing a vanadium oxide thin film for a microbolometer. The method is characterized by comprising the following steps of: (1) cleaning and blow-drying a substrate for later use; (2) performing reaction directly on the surface of the cleaned substrate to grow a net-like or intersected and interconnected carbon nano-tube film by using one of a chemical vapor deposition system reactor, an arc discharge system reactor and a laser ablation deposition system reactor and through the induction of a metal catalyst; (3) placing the substrate where the carbon nano-tube film grows into a vacuumized reactor, growing a layer of vanadium oxide film by using the reactor, dispersing the grown vanadium oxide film on the surface of carbon nano-tubes and in the gaps among the tubes, and annealing to form a vanadium oxide-carbon nano-tube composite film structure; (4) cooling the structure to room temperature and taking the structure out of the reactor; and (5) according to requirements, repeating the steps of carbon nano-tube growth, vanadium oxide deposition and annealing sequentially to form a vanadium oxide-carbon nano-tube multi-layer composite film structure.

Description

technical field [0001] The invention relates to the technical fields of uncooled infrared detection and uncooled terahertz detection, in particular to a thermistor material and light-absorbing material of a microbolometer, and a preparation method thereof. Background technique [0002] Infrared detectors convert invisible infrared heat radiation into detectable electrical signals to realize the observation of external affairs. Infrared detectors are divided into two categories: quantum detectors and thermal detectors. Thermal detectors, also known as uncooled infrared detectors, can work at room temperature, have the advantages of good stability, high integration, and low price, and have broad application prospects in military, commercial, and civilian fields. Uncooled infrared detectors mainly include three types: pyroelectric, thermocouple, and thermistor. Among them, the microbolometer focal plane detector based on thermistor is a kind of uncooled infrared detector that ...

AI Technical Summary

Problems solved by technology

However, since the electronic structure of the vanadium atom is 3d 3 4s 2 , the 4s and 3d orbitals can lose part or all of their electrons. Therefore, the traditional preparation methods of vanadium oxide films, such as magnetron sputtering, electron beam evaporation, laser pulse deposition, etc., have their own insurmountable shortcomings: namely The valence state of the V element in the prepared vanadium oxide thin film is complex, and the stability of the chemical structure of the thin film is poor, etc.

Due to the complex composition of the V element, small changes in the preparation process will have a greater impact on the chemical composition of the vanadium oxide film, resulting in significant changes in the electrical and optical properties of the film, which in turn affect the performance of the device.

Therefore, one of the main disadvantages of the microbolometer based on vanadium oxide film is that the preparation process of vanadium oxide film is difficult, and the repeatability and stability of the product are poor.

The disadvantage of co-sputtering metal doping is that the sputtering rate of metal impurities and vanadium oxide is difficult to keep consistent, so the ratio of vanadium oxide to metal in the film prepared by this method is often different from that of the target material, and the ratio is also different. May vary wildly with sputtering process fluctuations

The disadvantages of this inorganic sol-gel method are: (1) the temperature of sol preparation is too high, which affects device integration; (2) the product contains a large amount of non-metallic F impurities, which affects material properties; (3) the obtained vanadium oxide The light absorption rate is low, which is not conducive to the absorption detection of infrared light

Unfortunately, the conventional organosol-gel method contains some of the same disadvantages as the inorganic sol-gel method, including: (1) when the organic or inorganic sol-gel method is used for metal doping, the stability of metal impurities in the vanadium oxide film Poor performance, impurity diffusion, segregation and other phenomena are prone to occur, resulting in the degradation of the performance and quality of the vanadium oxide thin film, and it is difficult to meet the long-term operation needs of the device; (2) The method of metal doping by organic or inorganic sol-gel method cannot Effectively Improving the Light Absorption Properties of Vanadium Oxide Thin Films

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