Composite insulating layer for thin film sensor and preparation method of composite insulating layer

Abstract

The invention belongs to the technical field of thin film sensors, and relates to a composite insulating layer for a thin film sensor. The composite insulating layer comprises four layers of structures which comprise the amorphous Al-O-N diffusion impervious layer, the Al-O-N-to-Al2O3 transition layer, the electron beam evaporation Al2O3 thin film layer and the microcrystal Al2O3 oxygen diffusion barrier layer in sequence from bottom to top. An amorphous Al-O-N thin film in the composite insulating layer is good in compactness and is in an amorphous state, and a good diffusion barrier effect is achieved for metal atoms. The adhesive force between the amorphous Al-O-N layer and the Al2O3 layer can be effectively improved through the transition layer. The microcrystal layer on the Al2O3 thin film layer can effectively prevent outside oxygen atoms from diffusing into the Al-O-N layer at a high temperature, the amorphous state of the Al-O-N thin film in the high-temperature oxygen-enriched environment is kept, and therefore the composite insulating layer still has good insulation performance in the high-temperature oxygen-enriched work environment, and the stability and the service life of the thin film sensor in the high-temperature environment are effectively guaranteed.

Description

technical field [0001] The present invention is mainly devoted to the research and preparation of thin-film sensors, and belongs to the technical field of thin-film sensors, especially the research on thin-film sensors on the surface of aerospace turbine engine blades. Such thin-film sensors can be used to measure the temperature and stress distribution on the surface of turbine blades, etc. , providing relevant basic data for the research and design of the engine. Background technique [0002] The turbine engine is an important part of the aerospace aircraft. The turbine blades inside the engine work in the harsh environment such as high temperature and high pressure generated by gas combustion for a long time. The distribution of stress and temperature on the blade surface greatly affects the performance and performance of the engine. Therefore, the measurement of the distribution of temperature and stress on the surface of the engine turbine blade becomes very important. ...

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Problems solved by technology

Among them, the insulating layer has a crucial influence on the reliability and stability of the thin film sensor. The conventional insulating layer is a single layer of Al deposited by electron beam evaporation. 2 o 3 Thin film has the advantages of simple process and fast film forming speed, but due to the Al 2 o 3 It grows in a columnar shape, and the shadow effect between the columns will produce larger holes and gaps, and in the subsequent high-temperature annealing process, due to the amorphous Al 2 o 3 Crystalline as well as functional layers with Al 2 o 3 The difference in thermal expansion coefficient between layers, the stress release will make the Al 2 o 3 Microcracks appear in the film, affecting the Al 2 o 3 Density of thin-film insulating layers

When the noble metal functional layer is prepared by subsequent sputtering, due to the high energy of the sputtered metal atoms, it is easy to penetrate the loose Al 2 o 3 The insulating layer is connected to the lower alloy layer. At the same time, the thin film sensor works in a high temperature environment, and metal atoms are easy to diffuse into the lower alloy layer, resulting in the failure of the thin film sensor.

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