| 摘要 |
<p>PURPOSE:To prevent the deformation of the angular distribution pattern and the cross-over by employing the LaB6 single crystal chip as the thermion emission cathode thereby maintaining the initial characteristic of the thermion emission for long term, while to lengthen the service life of the thermion emission cathode and to improve the reliability of the molded electron beam exposing device. CONSTITUTION:The axial direction of the chip is in <100> or the equivalent one while the tip section is rectangular having the four sides which are the cross lines between the faces <100> and <111>. The side face of the pyramid is the face <111> or the equivalent one. When employing the LaB6 single crystal cathode chip having such shape, the work function of the face <100> at the tip will be approximately 2.4 eV while that of the side face <111> is approximately 3.3 eV, thereby thermion emission will occur at the face <100> having lower work function and scarsely occur at the side face having high work function. Furthermore the chip will never be deformed.</p> |
