Researchers in the US have developed a Schottky barrier diode using diamond with the highest reported reverse breakdown voltage over 4500V.
Using a diamond substrate for a diode opens up the use of the devices for the electricity grid.
The Diamond p-type lateral SBD developed at the University of Illinois Urbana-Champaign has a 2- μm -thick drift layer are fabricated with and without Al2O3 field plates.
Both SBD diamond diodes, with and without Al2O3 field plates, show rectifying ratios larger than 107 at room temperature, and a peak current density of 5.39 mA/mm under 40 V forward bias at 200 °C. The leakage current density at room temperature is stable at approximately 0.01 mA/mm for both diodes which is the lowest reported fro a diamond device.
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The SBD without the Al2O3 field plate exhibited a breakdown voltage of 1159 V, while the SBD with the Al2O3 field plate is stable under a reverse voltage of 4612 V. This is higher than many diamond SBDs previously reported and the voltage was limited by setup of measurement and not from the device itself. In theory, the device can sustain up to 9 kV.
“To meet those electricity demands and modernize the electrical grid, it’s very important that we move away from conventional materials, like silicon, to the new materials that we are seeing being adopted today like silicon carbide and the next generation of semiconductors—ultra-wide bandgap materials—such as aluminium nitride, diamond and related compounds,” says electrical and computer engineering professor Can Bayram, who led the research into the diamond diode design, along with graduate student Zhuoran Han.
“To have an electricity grid where you need high current and high voltage, which makes everything more efficient for applications such as solar panels and wind turbines, then we need a technology that has no thermal limit. That’s where diamond comes in,” said Bayram.
“We built an electronic device better suited for high power, high voltage applications for the future electric grid and other power applications,” said Han. “And we built this device on an ultra-wide bandgap material, synthetic diamond, which promises better efficiency and better performance than current generation devices. Hopefully, we will continue optimizing this device and other configurations so that we can approach the performance limits of diamond’s material potential.”