Study On The Third Generation Image Intensifier

With the help of night vision instrument, people can see the objects in the dark area. Night vision instrument has special applications in military field and study on it has not ever been stopping. In the half century of advent of night vision instrument, the study on the image intensifier made great progress and image intensifier was developed from the first generation to the fourth generation. This dissertation described the research results and relevant contents of study on the third generation image intensifier. GaAs has the structure of zinc blende and is a kind of direct band gap semiconductor. The transparent GaAs photocathode are usually made with plane (100) .So far there are still different explanations on surface structure of Cs-O layer of GaAs photocathode and on mechanism of electron escape from GaAs surface. The key making process of transparent GaAs photocathode is the growth of A1GaAs/GaAs epitaxial layers by MOCVD. The major factors of affecting growth quality of AlGaAs/GaAs epitaxial layer are reactor structure of MOCVD equipment, purity of gas and quality of GaAs substrate. High-resolution x-ray diffractometer is a powerful analysis tool on semiconductor epitaxial layer. Using it people can measure crystal parameter, strain, composition and stress of epitaxial layer. Because AIGaAs and GaAs epitaxial layer are grown in high temperature and have different thermal expansion coefficients, AlGaAs and GaAs will have different contractions when cooled down. The contraction distinction between AlGaAs and GaAs will lead to corresponding thermal strain. Consequently the thermal strain of AlGaAs/GaAs epitaxial layer will mainly depend on its growth temperature. Different growth temperature will result in different strain structure. Due to the thermal strain was existed in the AIGaAs/GaAs epitaxial layer, the diffracting angle of AlGaAs epitaxial layer will not solely depend on Al component in A1GaAs. Lattice space variation gradient produced by bent lattice and non-inference superimposition of AIGaAs/GaAs epitaxial layer all contributed to spreading out of FWHM of rocking curve. Thereby the FWHM of rocking curve of A1GaAs/GaAs epitaxial layers will not solely represent its crystallizing quality layer. Because thermal expansion coefficients of AIGaAs/GaAs and glass K4 are not same, thermal stress will existed between them after AlGaas/GaAs epitaxial layer bonded on glass K4.Thermal stress will make glass and epitaxial layer bend and this will make diffraction peak of rocking curve broaden along the 0) direction. The most effective method of reducing curve degree of AlGaAs/GaAs epitaxial layer is to let thermal expansion coefficient of A1GaAs/GaAs matching that of glass K4. Not only Ga of GaAs photocathode surface oxidized was, but As of GaAs photocathode surface during the baking of GaAs photocathode assembly. Once the Ga or As of GaAs surface was oxidized, it will make bad affection on the heat clean and active of GaAs photocathode. In view of this, GaAs photocathode can be baken before heat clean and active is proceeded. If?baking is necessary for GaAs photocathode, the vacuum degree of baking should lower than 1 0 Pa. In addition, this paper described the making technique of MCP iron barrier, house design, and In-seal equipment design. At last, this paper described the final results of study of the third generation image intensifier.