| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide high heat resistance and to prevent the migration by forming a lower electrode of an electron discharging part with a material having a higher melting point than Al, forming an insulating layer by an anodically oxidized film of Al or Al alloy, and forming a surface side of a protective insulating layer by an anodically oxidized film of Al or an Al alloy. SOLUTION: A metallic film for lower electrode is formed on an insulating board 1 such as glass by using Ta, Ti, Zr, Hf, Nb or their alloys. These materials are an electrode material having a higher melting point than Al, and an insulating layer of high withstand voltage is formed by anodic oxidation. Then a film is formed with an Al-Nd alloy including 2 atomic % Nd as an Al or the Al alloy film used as a material of an anodically oxidized film. Then a part excluding of the lower electrode 9 and an electron discharging part on the Al alloy film 11 masked by a resist 20, is selectively anodically oxidized thickly to form a protective insulating layer 14. As the Al2O3 anode of high withstand voltage is user as the protective insulating layer 14, the leakage of the current can be prevented.</p> |
