IMPROVED EMISSION STABILITY OF CARBURIZED HFC[100] AND ULTRASHARP TUNGSTEN FIELD EMITTERS

We have evaluated the cold-field-emission characteristics of HfC(100) and ultrasharp tungsten emitters. We found that proper acetylene treat ment improved both the angular current confinement and the emission st ability of thermally cleaned HfC(100) tips. Stable emission exceeding 10 mu A/sr for over 1 h and angular confinement to a 3 degrees semicon e angle have been observed, The improvements are probably related to t he modified work function and surface chemical composition induced by the acetylene treatment at the tip apex, Carburization of W(100) acid W(111) tips also significantly improved the emission current stability . This study indicates the usefulness of surface processing in the dev elopment of cold-field emitters. (C) 1995 American Vacuum Society.