| 摘要 |
PURPOSE:To improve the element manufacturing yield by a method wherein pinholes made in a cathode in case of forming gate part are filled with insulator and then cathode electrode is formed. CONSTITUTION:Pinholes 6 are made in an n emitter layer 1 to be filled with insulator 7. Such a material as thermosetting polyimide resin often used as an insulating film is applicable to this insulator 7 while overall surface of element is coated with said resin up to around 10mum thickness in terms of 20-30mum step difference between cathode 3 and gate 4. If the resin is provided with pertinent viscosity, the pinholes in cathode are completely filled with polyimide resin. Later, the polyimide resin is thermoset by baking process at 350 deg.C for 1-2hr and then this element is immersed in etching solution of polyimide resin mainly composed of hydrated hydrazine to completely remove the polyimide resin 7 on the surface of element. At this time, the pinholes 6 in the cathode are filled with the insulating resin 7 since the resin in the pinholes 6 is left as it is.
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