Gallium Oxide Transistor Handles More Than 8000V
Researchers at the University at Buffalo have developed a Ga2O3-based transistor that can handle more than 8,000V.
They think the transistor could lead to smaller and more efficient electronic power systems in electric cars, trains and airplanes. In turn, this could help improve how far these vehicles can travel. They published the results in the June edition of IEEE Electron Device Letters.
"To really push these technologies into the future, we need next-generation electronic components that can handle greater power loads without increasing the size of power electronics systems," says the study's lead author, Uttam Singisetti, who adds that the transistor could also benefit microgrid technologies and solid-state transformers.
Singisetti, PhD, associate professor of electrical engineering at the UB School of Engineering and Applied Sciences, and students in his lab have been studying the potential of Ga2O3, including previous work exploring transistors made from the material.
Ga2O3 has a bandgap of about 4.8 eV, which places it among an elite group of materials considered to have an ultrawide bandgap. SiC is 3.4 eV and GaN around 3.3 eV. Bandgap measures how much energy is required to jolt an electron into a conducting state. Systems made with wide-bandgap materials can be thinner, lighter and handle more power than systems made of materials with lower bandgaps.
A key innovation in the new transistor revolves around passivation to reduce the chemical reactivity of its surface. To accomplish this, Singisetti added a layer of SU-8, an epoxy-based polymer commonly used in microelectronics.
Tests conducted just weeks before the COVID-19 pandemic temporarily shuttered Singisetti's lab in March show the transistor can handle 8,032V before breaking down, which is more than similarly designed transistors made of SiC or GaN that are under development.
"The higher the breakdown voltage, the more power a device can handle," says Singisetti. "The passivation layer is a simple, efficient and cost-effective way to boost the performance of Ga2O3 transistors."
Simulations suggest the transistor has a field strength of more than 10 million volts (or 10 megavolts) per centimetre. Field strength measures the intensity of an electromagnetic wave in a given spot, and it eventually determines the size and weight of power electronics systems.
"These simulated field strengths are impressive. However, they need to be verified by direct experimental measurements," Singisetti says.
The research was supported by the US Air Force Office of Scientific Research and by the US National Science Foundation.
'Field-Plated Lateral Ga2O3 MOSFETs With Polymer Passivation and 8.03 kV Breakdown Voltage' by Shivam Sharma et al; IEEE Electron Devices Letters; Volume 41 Issue 6