Investigation of field emission characteristics of vacuum diodes and triodes with Nano- graphite-diamond-like Cathode

This paper presents a study of field emission properties of vacuum diodes and triodes with emitters based on nano-graphite-diamond-like films. Nano-graphite-diamond-like film was fabricated as a kind composite of nano-structured film where graphite layer has inclusions of nano-diamond crystallites. The novelty of proposed technical approach is based on nano-graphite-diamond-like components integration into conventional semiconductor wafer processing. Integrated two-electrode (diodes) and three-electrode (triodes) cells with a flat polysilicon electrodes 0.5 μm thick separated by insulating layers of 1.0 μm thick and through holes 2 μm in diameter to provide exposure of the lower electrode were used for emission properties testing. Nano-graphite-diamond-like layers were formed on the surface of the lower electrode. The lower electrode served as the cathode. The upper electrode served as anode. The middle electrode served as the control grid. The study was carried out under vacuum conditions with pressure of 1×10^-6 Torr and room temperature (300 K). While investigating auto-emission characteristics it was found that nano-graphite-diamond-like emitters demonstrate emission density up to 2 A/cm² along with quite low emission threshold voltage about 2.0 V/μm. Potential at the control grid of the triode provides higher emission current density.