Local field emission features of oriented diamond films on various silicon substrates

The field emission of diamond is promising for high-power applications. According to theoretical analyses, the field emission (FE) of insulating diamond should be governed by the diamond-substrate interface. Therefore, we have investigated the influence of different p- and n-doped Si(100)-substrate types on the FE properties of thick, oriented and locally insulating diamond films, grown in a microwave plasma-assisted CVD set-up. Local FE measurements were performed by means of a field emission scanning microscope with variable lateral resolution R/spl ges/100 nm. Very high maximum reproducible local current densities J/sub REP/ UP to 8860A/cm/sup 2/ could be achieved at field strengths E of typical 1000-3000 V//spl mu/m. The current I vs. E behaviour, the reproducibility and J/sub REP/ depended strongly on the substrate type. FE mapping over a 10/spl times/10 /spl mu/m/sup 2/ sized area revealed an uniform emission on a 100 nm scale. Therefore, smooth surfaces in a diode configuration as well as an optimisation of the substrate-diamond interface might be promising for power applications.