Properties Of Microchannel Plate Thin-film Dynode Based On Atomic Layer Deposition Technology

Microchannel plate?MCP?is a two-dimensional vacuum electron multiplied device with high aspect ratio structure.MCP can be used in many scientific applications,such as night vision devices,image photon counter,photomultiplier,electron microscopy,time-of-flight mass spectrometry and neutron detector.The properties of traditional MCP limited by its fabrication process.The resistance characteristics of the conductive layer and the secondary electron emission property of the emissive layer are limited by the material of the microchannel array.And the positive ion feedback effect caused by hydrogen reduction to form dynode will also affect its performance.Thin-film dynode of advanced technology microchannel plate?AT-MCP?fabricated using low pressure chemical vapor deposition?LPCVD?and thermal sensitization technology has many defects,such as quality of film,thickness control and conformal coating with high aspect ratio structure.However,Atomic layer deposition technology?ALD?is more advantageous than traditional MCP dynode technology and AT-MCP thin-film dynode technology in quality of film,thickness control and conformal coating with high aspect ratio structure.And,plastic MCP thin-film dynode can deposited by ALD technology at low temperature.Therefore,the ALD technology is a powerful way for high performance MCP development.In this thesis,the thin-film dynode consists of a conductive ZnO/Al2O3?AZO?thin film layer and an emissive SiO₂ thin film layer.The AZO thin films and SiO₂ thin films were deposited on plane substrate by Atomic layer deposition technology.The sheet resistance of ALD-AZO thin films and the secondary electron emission yield of ALD-SiO₂ thin films were investigated.It is guiding significance for the thin-film dynode of MCP deposited by ALD technology.The structure of thin-film dynode was designed.The ideal formula of Zn content in ALD-AZO thin film was modified.The change of the structure of ALD-AZO thin films analyzed by SEM.The Zn content in different structure ALD-AZO thin films measured by ICP-AES.The effect of deposition temperature,the percentage of ZnO cycle,and the structure of films on the sheet resistance of ALD-AZO films were investiaged that in order to satisfy the requirement of resistance of conductive layer.Finally,the secondary electron emission of ALD-SiO₂ thin films were studied.The results show when modify the formula of ideal Zn content,the corrosion coefficient ? should be 0.6823.If both the number of layers of ZnO and Al2O3 are large,will generate a nanolaminate.However,if both the number of layers of ZnO and Al2O3 are small,will generate a AZO alloy film.The sheet resistance of ALD-AZO thin films satisfy the requirement of resistance of conductive layer when both the number of layers of ZnO and Al2O3 within 10,the deposition temperature more than 170?,and the percentage of ZnO cycle within 20⁶6.7%.When the thickness of ALD-SiO₂ thin film is 5nm,the secondary electron emission property of the ALD-SiO₂ thin film satisfy the requirement of emissive layer.