Diamond is a superior material with unique properties
among wide
band gap semiconductors; it is the most promising candidate for power
devices due to its high breakdown voltage and low power losses. The
heteroepitaxially grown diamond has been introduced to overcome the
size limitation of homoepitaxial plates. Nevertheless, several properties
still need to be reported, such as the size upscaling compatibility
of Schottky diodes to power electronics devices. Therefore, the performance
of pseudovertical Schottky diodes fabricated on heteroepitaxial diamonds
has been investigated as a function of device size. Electrical characteristics
for more than 100 Schottky barrier diodes (SBDs) have been studied;
they can be categorized as 1 mm X-SBDs, 200 μm X-SBDs, 90 μm
X-SBDs, and 65 μm X-SBDs, where X is Mo, Cr, and Pt. The Schottky
barrier height showed a dependency on the device size; for the Mo-SBDs,
the barrier height increased from 1.29 to 1.58 eV for 65 μm
and 1 mm diameters at room temperature, respectively. Similar behavior
was also observed for Cr and Pt devices. In addition, there is a severe
reduction in the specific-on resistance for small-diameter SBDs. The
high-temperature dependence of the device parameters and performance
was also studied. All SBDs showed a decrease in the ideality factor
and specific-on resistance with the temperature, in addition to the
increase in the barrier height. The breakdown voltage was enhanced
by 6-fold for the 65 μm compared with 1 mm Mo-SBDs. 90 and 65
μm devices showed a promising potential for power applications
according to Baliga’s power figure of merit that exceeded 5
MW/cm2 for 65 μm Pt-SBDs as well as the breakdown
voltage of 453 V which represents the best-reported value for the
heteroepitaxial-diamond-based device.