Development Of High Temperature Electron Bombardment Evaporator

As one of the key equipments of vacuum coating, the molecular beam epitaxy evaporatorhas an extremely important influence on the coating result. In order to obtain high-qualityperformance of the film, the good performance of the evaporator is needed. There are muchresearch on molecular beam epitaxy evaporator abroad, but in our country, the time of studyon molecular beam epitaxy evaporator is short. In particularly, the high-quality evaporatorsare almost entirely dependent on import used in ultra-high vacuum. To compensate for thedeficiencies of the field, on the basis of the analysis of simple evaporator, the ultra-highvacuum high temperature electron bombardment evaporator is developed. It is of greatsignificance to develop the thin film technology and new materials. The following works arecompleted in this paper:Firstly, by analyzing the work principle of high temperature electron bombardmentevaporator (HTEBE), and simple evaporator for the design basis, The overall design of HTEBE isdetermined, which contains the design of baffle mechanism, rotary linear drive mechanism,water-cooled mechanism, heating mechanism, beam testing mechanism and connectingchamber. The selection of materials in different parts is determined by analyzed. By furtheranalysis and calculations, the length of the heating wire, the location of the filament and thecrucible and the position of the crucible can be fixed.Secondly, based on the overall design plan, the specific structures of the component partsof HTEBE are optimal designed. The baffle mechanism designed can realize the transfer ofrotary motion; rotary linear drive mechanism can move the position of the crucible in thevacuum before and after by operating this mechanism outside of the vacuum, and can adjustthe distance between the crucible and the tungsten wire. The cooling dome used of copper asthe material is not only to achieve a good cooling effect, which makes the crucible heated tohigh temperature, other parts of the temperature below100℃, but also to ensure the degree ofvacuum; the guidance nozzle designed makes the beam can be directed to the substrate; thebeam testing mechanism designed can monitor the rate of the beam flux; the filament currentconductor, ion current collector wire and the thermocouple wire are integrated with anintegrated six-needle electrode.Thirdly, the performances of evaporators are tested by building a test platform. Thetesting performances include voltage, current, temperature, evaporation rate and molecularbeam distribution, and the parameters obtained are analyzed.The testing results show that: EB evaporator not only can cover a wide temperaturerange, but also reach the thermal equilibrium in a shorter time and produce a highly stable uniform beam flux. It is demonstrated to meet the demands of MBE growth in ultra-highvacuum completely.