High-temperature characteristics of Ag and Ni/diamond Schottky diodes

The high-temperature characteristics of diamond Schottky diodes fabricated using Ag or Ni on in-situ boron-doped diamond were examined. Up to 600 °C, Ag Schottky diodes exhibited a high rectification ratio of the order of 104. Even at ~ 750 °C, their rectification ratio was about 10, indicating that diamond field effect transistors with Ag Schottky diodes can operate at this temperature. In contrast, Ni Schottky diodes did not show clear rectification above 600 °C. An analysis of the I-V curves indicated that the Ag Schottky diodes have a higher rectification ratio than the Ni Schottky diodes at high temperatures due to their higher barrier heights (ϕB = ~ 2.0 and ~ 0.7 eV for Ag and Ni, respectively).