Concept of uniformity of electric heating tube film:

Concept of uniformity of electric heating tube film:

The process of vacuum deposition is very complicated. Due to the different coating principles, it can be divided into many types. It has a unified name just because it needs high vacuum. Therefore, for vacuum deposition with different principles, the factors affecting the uniformity are also different. And the concept of uniformity itself also has different meanings depending on the coating scale and film composition.

1. Uniformity in thickness can also be understood as roughness. From the perspective of optical film scale (that is, 1/10 wavelength as a unit, about 100A), the uniformity of vacuum deposition is quite good, and the roughness can be easily controlled within 1/10 of the visible light wavelength, which means that there is no obstacle to vacuum deposition for optical characteristics of the film. However, if it refers to the uniformity on the atomic layer scale, that is, to achieve 10A or even 1A surface flatness, it is the main technical content and technical bottleneck in vacuum deposition. The specific control factors will be explained in detail according to different coatings.

2. Uniformity of chemical composition: that is to say, in the film, the atomic composition of the compound will easily produce non-uniform characteristics due to the small size. If the coating process of SiTiO3 film is not scientific, then the actual surface composition is not SiTiO3, but may be other examples. The coated film is not the chemical composition of the desired film, which is where the technical content of vacuum deposition lies.

3. Uniformity of lattice order: This determines that the film is single crystal, polycrystalline, and amorphous, which is a hot issue in vacuum deposition technology. See below for details.

There are two main categories: evaporative deposition coatings and sputtering deposition coatings, including many types, including vacuum ion evaporation, Magnetron sputtering, MBE molecular beam epitaxy, sol gel method, etc

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