HAFNIUM CARBIDE FILMS AND FILM-COATED FIELD-EMISSION CATHODES

We have previously reported on field emission improvements, in turn-on voltages and emission stability using ZrC films as coatings on Si and Mo single emitters and emitter arrays. However, during our emission s tudies of bulk carbides, HfC was found to be slightly superior. We now report on work in progress investigating HfC films and HfC film coate d field emission cathodes. Uses for arrays of these field emission cat hodes range from video displays to microwave applications. This articl e deals with physical vapor deposition of HfC, absolute work function measurements, and electron emission properties of these film surfaces. This work demonstrates improvements by using HfC films over films of ZrC and an associated surface work function lowering of more than 1 eV in some instances compared to the clean surface. (C) 1998 American Va cuum Society.