Preparation method of secondary-electron emission thin film

Abstract

The invention discloses a preparation method of a secondary-electron emission thin film. The preparation method comprises the following steps: (1) depositing a buffer layer on a metal substrate; (2) depositing a magnesium oxide and metal mixed layer on the buffer layer by sputtering a magnesium target/magnesium oxide target and sputtering other metal targets; (3) depositing a surface on the magnesium oxide and metal mixed layer. In the step (2), the two targets are used for respectively depositing magnesium oxide and other metals, the sputtering power, the sputtering time, the flow rates of working gas and reactant gas and the temperature of the substrate are individually controlled so as to prepare the magnesium oxide and metal mixed layer with proper magnesium oxide and metal grain size, magnesium oxide crystallization orientation, metal content and distribution of metal grains in a membrane layer and thickness of the membrane layer. The secondary-electron emission thin film prepared by the method has high secondary electron emission yield and good electrical conductivity, and therefore, the secondary-electron emission thin film has high secondary-electron emission stability.

Description

technical field [0001] The invention belongs to the technical field of optoelectronic materials and devices, and relates to a preparation method of a secondary electron emission film that can be used for an electron multiplier. Background technique [0002] Magnesium oxide (MgO) thin films are widely used in image intensifiers, photomultiplier tubes, electron multipliers, orthogonal field amplifiers and devices such as plasma displays. When used in an electron multiplier, in order to obtain a long service life of the device, the secondary electron emission film must be able to withstand the long-term bombardment of a high-power electron current, so the thickness of the prepared MgO film needs to reach tens of nanometers or even a hundred above nanometers. However, since magnesium oxide is an insulating material, the thicker MgO film will produce surface charging phenomenon under the bombardment of electron flow, which will make its secondary electron emission coefficient d...

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Problems solved by technology

However, the thickness of the MgO layer on the surface of the film prepared by this method is difficult to accurately control. If the surface MgO layer is too thick, the conductivity of the film will be reduced, thereby affecting the stability of secondary electron emission. If it is too thin, the secondary electrons of the film will be reduced. Emission coefficient

And, Ar + Sputtering treatment will cause damage to the surface magnesium oxide grains and reduce the secondary electron emission coefficient of magnesium oxide

especially since Ar + The difference in the sputtering rate of various metals and magnesium oxide is also different. Some metals have little difference in the sputtering rate of MgO due to their low sputtering rate or strong binding force with MgO. Use this method to prepare thin layers with high MgO content on the surface, so this method is less applicable to prepare MgO thin films doped with different metal materials

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