Pseudo-vertical Mo/Au Schottky diodes on {113} oriented boron doped homoepitaxial diamond layers

Abstract

Pseudo-vertical diodes on {113} oriented homoepitaxial boron-doped diamond were successfully fabricated using molybdenum as a metal for both the Schottky and ohmic contacts. After metal deposition, diodes were stabilized by annealing for 20 min at 300 °C and their I-V and C-V characteristics were measured at temperatures from 30 to 180 °C. Results show that Mo forms a very good and stable Schottky contact on {113} oriented homoepitaxial boron-doped diamond. At 180 °C, forward current densities higher than 1kA/cm2 are achieved, while the reverse current density stays unchanged at 10−8 A/cm2. The ideality factor of the diode I-V characteristic drops to 1.23 and the barrier height of the Schottky contact increases to 1.71 eV. This effect is attributed to inhomogeneity in the Schottky barrier. These characteristics are fully comparable with those of the best Schottky diodes fabricated on {100} oriented homoepitaxial boron-doped diamond. Results confirm that the use of {113} oriented homoepitaxial boron-doped diamond for the fabrication of high-temperature power devices is advantageous, as it enables high quality Schottky and ohmic contacts.