Enlargement of effective area in Schottky barrier diodes on heteroepitaxial (001) diamond substrates by defect reduction and their radiation tolerance.

A major obstacle to realizing diamond electronics is the presence of device-killing defects. Characteristics of diamond-based diodes are degraded with increasing contact size, and a large Ohmic-like leakage current can be generated. Here, we introduced a buffer layer to suppress the killer defects, which extended from the substrate to the epitaxial layer. With the utilization of the buffer layer created using the metal-assisted termination (MAT) technique, Schottky barrier diodes (SBDs) with diametric sizes of Schottky contact ranging from 65 to 1000 μm were fabricated on heteroepitaxial-grown diamond (001) substrates. The SBDs exhibited an explicit rectifying behavior with a rectification ratio of >1010 even with 1000 μm circular contact (7.85 × 10−3 cm2). Satisfying diode parameters were obtained with an ideality factor of 1.52, a Schottky barrier height of 1.66 eV, and a picoampere of leakage current at a reverse bias of 10 V. Interestingly, the diode parameters of the diamond-based SBDs such as ideality factor, Schottky barrier height and rectifying ratio were likely not changed or degraded even after absorption to 1 MGy in the dose of white X-ray. Overall, this demonstration indicates a promising way to realize a large active area of diamond electronics that is applicable to high-output power transmission devices and detector applications. [Display omitted] • A large area of Schottky contact with a diameter of 1 mm is fabricated on a heteroepitaxial-grown diamond (001) substrate. • 1 mm Schottky barrier diode exhibits a rectifying ratio > 1010 with picoampere-scale leakage current. • The metal-assisted termination (MAT) technique effectively suppresses dislocation propagation from the substrate to the drift layer. • Diamond-based Schottky barrier diodes tolerate against absorption doses of highly energetic X-rays of at least 1 MGy. [ABSTRACT FROM AUTHOR]