A Gallium Nitride Transistor Withstood More Than 3,400 Volts
EPFL researchers built a gallium-nitride transistor on silicon that withstood more than 3.4 kilovolts while keeping resistance low. Its charge-balanced design could shrink high-voltage power converters, but it remains a laboratory device without demonstrated converter-level efficiency, manufacturing yield or long-term field reliability.
Researchers at EPFL have built a gallium-nitride power transistor on a silicon substrate that withstood more than 3.4 kilovolts before electrical breakdown. The device uses the material's own polarization to balance positive and negative charge, spreading voltage across the transistor instead of concentrating it at one vulnerable point.
The 30-second summary
- What happened? A new gallium-nitride design produced transistors with breakdown voltage above 3.4 kV and related diodes above 3.9 kV.
- Why does it matter? High-voltage switches with low resistance could make power conversion smaller and more efficient in data centers, electric vehicles and renewable-energy systems.
- What is the catch? These are laboratory components, not finished converters. Manufacturing yield, lifetime, switching losses at system level and cost have not been established.
Key number: More than 3.4 kV, over five times the roughly 600 to 650 V rating common among commercial gallium-nitride power devices cited by the researchers.
Why high voltage usually causes failure
Gallium nitride (GaN) can switch power efficiently because it tolerates stronger electric fields than silicon and can operate with low resistance. Yet in lateral GaN devices, charge can accumulate unevenly when the switch turns off. The resulting electric-field spike may break the device down before the entire semiconductor is carrying the voltage evenly.
Engineers have long used superjunction structures to distribute an electric field. Conventional versions depend on precisely doped regions of positive and negative charge, a balance that can become difficult to maintain across temperature and manufacturing variation.
The polarization approach
The EPFL team instead layered III-nitride materials so their natural spontaneous and piezoelectric polarization created two mobile sheets: electrons in one channel and positive holes in another. Matching these charges preserved neutrality through the drift region as the device switched off, producing a more uniform electric field without intentional chemical doping.
The paper reports Schottky diodes exceeding 3.9 kV with specific on-resistance as low as 4.7 milliohm-square-centimeters. Transistors exceeded 3.4 kV, while dynamic on-resistance rose by less than 15% during tests up to 3 kV. The devices also showed repeatable breakdown behavior across temperature.
Before we overstate the result
Breakdown voltage is only one requirement for useful power electronics. A commercial converter must also switch repeatedly with low losses, survive years of thermal and electrical stress, connect safely to packaging and be manufactured at consistent yield. The study demonstrates device physics and fabrication on silicon, but not a production-ready charger, grid inverter or data-center power supply.
What happens next
The researchers plan to combine the voltage-balancing structure with multiple conduction channels developed in complementary work. The aim is to handle very high voltage while further reducing resistance and heat. That combined device, followed by packaged-module and converter testing, will determine whether the laboratory advantage survives in real power systems.
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