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

Pseudo‐Vertical Schottky Diode with Ruthenium Contacts on (113) Boron‐Doped Homoepitaxial Diamond Layers

“…Specific contact resistance of Ru/Au contacts (circles–annealed at 650 °C) deposited on an ozone‐treated (113) homoepitaxial BDD layer versus N A −1/2 (room temperature measurement). The recently measured [ 8 ] values for Mo/Au (open boxes—annealed at 650 °C) and Ti/Au contacts (open triangles—annealed at 500 °C) are shown for reference.…”

“…Prior to contact deposition, the sample surfaces were ozone treated by a lab-made system at 150 °C and atmospheric pressure for 20 min with the assistance of UV light illumination to obtain a clean oxygen-terminated surface. [8] Schottky, on the top p À layer, and ohmic contacts, on the p þ contact layer, were realized by the e-beam evaporation of Ru/Au metallic bilayer according to the procedure described above. Since Ru (see Section 3.1) forms an excellent ohmic contact on (113)-oriented BDD with metallic conductivity, a single metallization can be used for the creation of pVSBDs.…”

“…Prior to contact deposition, the sample surfaces were ozone treated by a lab‐made system at 150 °C and atmospheric pressure for 20 min with the assistance of UV light illumination to obtain a clean oxygen‐terminated surface. [ 8 ]…”

“…This value is slightly lower than the value 0.86 AE 0.14 eV determined from the XPS measurement in the study of Song et al [15] Figure 5 also compares the Ru data with R Csp values which were recently obtained for molybdenum and titanium contacts deposited on (113)-oriented heavily doped BDD layers. [8] While titanium is a favorite choice for the fabrication of ohmic contacts, molybdenum as a refractory metal can either be used for the realization of rugged ohmic or Schottky contacts. The comparison shows that Ru/Au contacts can achieve very low values of the specific contact resistance values approaching those of Ti/Au.…”

“…Several refractory metals, which provide high resistance to thermal and environmental stresses, allow the realization of both types of contacts on oxygen‐terminated boron‐doped diamond (BDD). High‐quality rectifying and ohmic contacts were, for example, reported for molybdenum [ 3–8 ] and zirconium. [ 9–11 ] Ruthenium was also successfully used for the realization of vertical [ 12–14 ] and pseudo‐vertical [ 4 ] SBDs.…”