Preparation Of MCP Anti-Ion Feedback Membrane Based On PEALD

Microchannel plate（MCP）is an electron multiplier,which is the core device of image intensifier.In the third-generation low-light-level image intensifier,the input surface of the MCP is covered with an anti-ion feedback film to suppress the feedback of positive ions,prevent damage to the cathode,and improve the life of the image tube.Traditional anti-ion feedback membrane preparation technology has problems such as uneven membrane layer,difficult to accurately control thickness,carbon pollution,and incomplete removal of organic membranes.Based on the advantages of atomic layer deposition（ALD）technology,this paper proposes a new pollution-free anti-ion feedback membrane preparation method and explores some key technologies in the preparation process.Through the study of the principle of ALD,the advantages of ALD film preparation are obtained.The advantages of thermal atomic layer deposition（TALD）and plasma-enhanced atomic layer deposition（PEALD）are compared and analyzed.By establishing the precursor diffusion kinetic model,the relationship between the precursor surface coverage S and time t and temperature T at saturation was obtained.Through the Monte Carlo method,the 3D model of the microchannel plate anti-ion feedback film was established by using the SRIM program.The Stopping Range Tables and TRIMCalculation modules were used to simulate the ion barrier properties of Al₂O₃ and Be O films with different incident energy,film thickness and film density.The anti-ion feedback film material was determined to be Al₂O₃ film,and the thickness of the anti-ion feedback film was determined.Al₂O₃ films were prepared on Si substrates by PEALD technology.The effects of substrate hydroxylation on the growth of Al₂O₃ films were studied.The effects of different process parameters on the deposition of Al₂O₃ films by low temperature PEALD were discussed.The effects of temperature and discharge power on the morphology and growth rate of Al₂O₃ films were studied.It is found that the growth rate of PEALD-Al₂O₃ thin film on Si substrate decreases slowly with the increase of deposition temperature,and the surface roughness of the film decreases first and then increases with the increase of deposition temperature.With the increase of discharge power,the growth rate of the film increases,and the surface roughness of the film decreases first and then increases.The substrate hydroxylation deposition experiment showed that the surface reaction sites of the hydroxylated Si substrate increased significantly.PEALD-Al₂O₃ films were prepared on PET substrates.The effect of surface hydroxylation of organic substrates on the deposition of Al₂O₃ films by PEALD was discussed.The effects of temperature and discharge power on the preparation of Al₂O₃films on organic substrates were studied.When the deposition temperature is 60°C,there are some island Al₂O₃ on the substrate surface.With the increase of temperature,the island Al₂O₃ on the substrate surface gradually increases.At 120°C,the film is about to be formed,and the roughness also increases with the increase of temperature.When the discharge power is 50 W,there are some island Al₂O₃ on the surface of the substrate.With the increase of discharge power,the island Al₂O₃ on the surface of the substrate gradually increases.With the increase of discharge power,the concentration of oxygen free radicals increases,and the chemical adsorption with TMA precursor increases,which makes the island Al₂O₃ deposited on the surface of the substrate film increase and the roughness increases.The reaction sites on the surface of the hydroxylated organic substrate increase significantly,and the hydroxylation pretreatment on the surface of the organic substrate plays an important role in preparing a uniform and dense film.