ENHANCED ELECTRON-EMISSION FROM PHOSPHORUS-DOPED AND BORON-DOPED DIAMOND-CLAD SI FIELD EMITTER ARRAYS

A new fabrication technology of polycrystalline diamond-clad Si microt ips using microwave plasma chemical vapor deposition (MPCVD) has been developed to improve the characteristics of electron field emission fr om the pure Si tips. A uniform and smooth coating morphology for the d iamond-clad Si tips have been achieved. Electron emission currents of diamond-clad tips are much higher than those of pure Si tips. Such gre at improvement is attributed to the lowering of the effective work fun ction in the diamond-clad tips. The effects of phosphorus- and boron-d oped diamond-clad Si tips have been also studied in comparison with th e undoped ones. The current-voltage characteristics of the undoped dia mond-clad tips were further enhanced by the in-situ doping of phosphor us or boron due to a higher electron supplement. Moreover, the P-doped diamond-clad tips show a better field emission performance as compare d to the B-doped ones. This difference is surmised to be associated wi th the higher electron conductivity and defect densities of P-doped di amond films.