GaN-on-Si MOSHEMT sets new record
Belgian research hub Imec has claimed a new benchmark in RF transistor performance for mobile applications with a GaN-on-silicon MOSHEMT (metal-oxide-semiconductor high-electron-mobility transistor) that achieves both record efficiency and output power for a low voltage enhancement-mode device.
The results, which mark a crucial step toward integrating GaN technology into mobile devices in the 6G FR3 band between 7 and 24GHz, will be presented at the 2025 Symposium on VLSI Technology and Circuits in Kyoto, Japan.
The GaN-on-Si e-mode MOSHEMT reached a record 27.8dBm (1W/mm) output power and 66 percent power-added efficiency (PAE) at 13GHz and 5V. The result was obtained in a single device with an eight-finger gate layout, providing the gate width needed for high output power without requiring the combined power of multiple transistors. The performance was enabled by combining a gate recess technique, used to shift the device into e-mode, with an InAlN barrier layer that offsets the performance loss from the thinned channel.
In parallel, Imec also demonstrated a record-low contact resistance of 0.024Ω· mm maximising current flow and minimising power loss. While the result was obtained in a separate module, it is fully compatible with the e-mode transistor architecture. Imec's simulations indicate that integrating this contact module could improve the output power density by 70 percent, meeting the performance target for 6G user equipment.
“Reducing contact resistance is crucial for pushing output power while keeping efficiency high,” said Alireza Alian, principal member of technical staff at Imec. “Our next step is to integrate this contact module into the e-mode transistor and validate the expected gains in power and efficiency, bringing the device closer to real-world 6G applications.”
