Local field emission features of thick 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 differently 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 chemical vapor deposition setup. Local FE measurements were performed by means of a field emission scanning microscope with variable lateral resolution R⩾100 nm. By using anodes of 1 μm tip diameter, very high maximum reproducible local current densities JREP (from μm2-sized areas) up to 8860 A/cm2 could be achieved at vacuum field strengths E of typical 1200–3000 V/μm, corresponding to 20–50 V/μm in the diamond near the substrate. The current I vs E behavior, the reproducibility, and JREP depended strongly on the substrate type. FE mapping over a 10×10 μm2 sized area revealed a uniform em...