Low-resistance ohmic contacts on boron-doped {113} oriented homoepitaxial diamond layers

Abstract

Refractory metals (titanium, molybdenum, and zirconium) with a gold overlayer were used to form ohmic contacts on {113}-oriented boron-doped diamond epitaxial layers. Morphology and thickness of deposited layers were determined by AFM and X-SEM; resistivity, carrier concentration, and mobility were determined by Hall measurement. Specific contact resistance of evaporated Ti/Au, Zr/Au, and Mo/Au contacts was measured using c-TLM structures after different annealing stages at temperatures up to 850 C. Results show that on layers with {113} orientation it is possible to achieve ohmic contacts of comparable quality as for layers with {100} orientation. In summary, this study confirms the suitability of {113} oriented boron-doped diamond epitaxial layers for the fabrication of diamond power electronic devices with excellent ohmic contacts.