Fabrication of Dual-Barrier Planar Structure Diamond Schottky Diodes by Rapid Thermal Annealing

Fabrication of dual-barrier planar (DBP) structure diamond Schottky barrier diodes (SBDs) with only Ni Schottky contact was carried out by rapid thermal annealing. Ni/Au narrow stripes were first patterned on p- layer and annealed at 550 °C to decrease Schottky barrier height and form low barrier contact. Then, Ni/Au Schottky electrodes were deposited on the window area between stripes to serve as high barrier contact. Ti/Pt/Au ohmic contact was formed on the back side of p+ diamond substrate. The fabricated DBP structure SBDs exhibit low forward voltage drops compared with single high barrier diode, and reverse leakage current densities of two to three orders of magnitude smaller than that of single low barrier diode. The influence of stripes area proportion on device properties was investigated and the barrier height can be adjusted by changing dual-barrier ratio. This new device structure displays a small power dissipation of 0.54 W/cm2, which is a promising technology for high power diamond diodes.