Field emission measurements with /spl mu/m resolution on CVD-polycrystalline diamond films

We have investigated the distribution of field emitting sites on polycrystalline diamond films at electrical surface fields between 2.5 and 150 MV/m by means of a Field Emission Scanning Microscope with /spl mu/m resolution. For the first time field emission scans were performed on broad-area (/spl ap/cm/sup 2/) diamond cathodes with in situ scanning electron microscope analysis of the localized sites. The 2-3 /spl mu/m thick diamond films were chemical vapor deposited on Mo substrates by the hot-filament technique. Undoped and p-type boron doped films with low content of sp/sup 2/-bonded carbons were studied. The highest emitter density of 800/cm/sup 2/ at 100 MV/m was detected on undoped diamond surfaces. A preliminary study of localized emitters indicated both sporadic particles of foreign materials at the emitting sites as well as intrinsic emission from diamond. In addition, the Fowler-Nordheim parameters /spl beta/ and S, the elemental composition, and the current stability of localized emitters were measured.