Researchers Develop Efficient W-Band GaN Semiconductor
New passivation-free transistor technology on sapphire offers a path to lower-cost millimeter-wave power applications.
Updated on Oct. 26, 2026 in Semiconductors
Researchers have demonstrated a passivation-free Ga-polar recessed-gate AlGaN/GaN high-electron-mobility transistor (HEMT) designed for W-band operation. This device achieved an output power density of 2.8 W/mm and 26.8% power-added efficiency at 94 GHz.
Why it matters
The use of sapphire substrates provides a cost-effective alternative to silicon carbide, while the device's simplified epitaxial design reduces fabrication complexity. This technology could become a key candidate for high-frequency millimeter-wave power applications.
The device features a 5.5-nm Al0.35Ga0.65N barrier under the gate and a 31-nm barrier in the gate access regions, achieving a peak transconductance of 750 mS/mm. It exhibits a drain current density of 1.7 A/mm, a gate on/off ratio of 10^7, and reaches a maximum oscillation frequency of 203 GHz.
The details
Fabricated on a sapphire substrate, the transistor underwent continuous-wave load-pull measurements at 94 GHz to verify its performance. The architecture successfully avoids passivation, streamlining the production process compared to complex N-polar device designs.
Timeline
October 2026: The performance metrics for the HEMT device were formally reported.
The Tech Race
This development marks a significant departure from N-polar GaN transistor fabrication techniques by utilizing a simpler epitaxial design. By moving to sapphire substrates, the technology challenges the dominance of more expensive substrates in the high-frequency power electronics market.
Advancements in high-efficiency W-band transistors could eventually lead to lower manufacturing costs for next-generation communication equipment. This shift may help developers scale millimeter-wave applications more affordably in future wireless infrastructure.
The takeaway
This research demonstrates that high-performance millimeter-wave power applications can be achieved through simplified, low-cost fabrication methods. Engineers looking to optimize power-added efficiency may find this passivation-free architecture a viable path for future designs.
Further reading
Learn more about the latest innovations in high-frequency hardware on our Semiconductors page.
Source note: This article includes information reported by MTT-S.
