Single Crystal Of Lab <sub> 6 </ Sub> Field Emission Diode Array Study

Vacuum microelectronic devices based on field emission theory have been paid more and more attention, because they have not only the advantages of semiconductor devices such as small size and low power consumption, but also the advantages of vacuum electronic devices such as high speed, high frequency, high temperature resistance and radiation resistance. As the core content of vacuum microelectronics, the performance of field emitter array (FEA) directly influences the whole performance of field emission device. Recently, lots of measures such as mending the material, structure or manufacturing technology of FEA have been taken to improve the whole performance of cathode. At present, conventional field emitter arrays have molybdenum (Mo) FEA fabricated by double-source rotation evaporation and silicon (Si) FEA fabricated by wet or dry etching with semiconductor technology. However, these two cathodes have their respective shortcomings, for example, Mo FEA has poor adhesion with substrate, and Si FEA has poor heat stability, low emission reliability and restricted emission current.In this paper, lanthanum hexadboride (LaB₆) was chosen as the ideal material of FEA for its advantages such as good heat stability and chemical stability, also low work function, high conductivity and activated surface. In the aspect of structure of FEA, the optimal structure was obtained considering both quality parameter and emission stability of emitters. As to the manufacturing technology of LaB₆-FEA, the method of semiconductor manufacturing technology together with electro-chemical corrosion was introduced considering both mature semiconductor technology and the high chemical stability of LaB₆ material.The manufacturing technologies of LaB₆-FEA included mainly three parts, which were the deposition of mask layer, the patterning of mask layer and electrochemical corrosion. In this paper, SiN_x film was chosen as the mask material used in the electrochemical corrosion of LaB₆, and this film was deposited by Plasma enhanced chemical vapor deposition (PECVD). The patterning of SiN_x film was done by the micromachining technologies of semiconductor technologies, mainly including photo- lithography and etching, and in this paper the patterning of mask layer was done by projection exposure method and reactive ion etching (RIE). Electrochemical corrosion was the key component in this paper. A large number of experiments were made to find out the optimal technology parameters, including the type and deepness of electrolyte, the current of electrolyze, the time of electrolyze, etc. And then, the field emitter arrays with good surface appearance, height and roughness were obtained.Finally, the performance of fabricated LaB₆-FEA was tested, and experimental phenomenon and data were discussed and analyzed in detail. The results showed that this field emitter array had good field emission performance and stability.