Research hub Imec has achieved what it claims is a record-breaking achievement in RF gallium nitride on silicon (GaN-on-Si) transistor performance that could be a boon for next-generation 6G smartphones.
The GaN metal-oxide-semiconductor high-electron mobility transistor (MOSHEMT) on silicon that achieves both record efficiency and output for an enhancement mode (e-mode) device operating at low supply voltage. Imec said it demonstrated a record-low contract resistance of 0.024 Ω · mm.
The technology could be a step toward integrating GaN technology into next-generation mobile devices, particularly those in the 6G FR3 band between 7 and 24 GHz.
Why it matters
To meet the demands of future 6G infrastructure and devices, higher frequences are needed.
Current smartphones and mobile devices based on gallium arsenide (GaAs) struggle to maintain performance at 6G frequencies. GaN can be used as an alternative because of its higher power density and breakdown voltage. GaN transistors on silicon carbide (SiC) have shown strong RF performance in high-frequency base station applications, Imec said.
GaN-on-Si is considered the best of both worlds marrying the high performance for GaN transistors with the scalability and cost-effective platform of silicon. However, it is a challenging design due to the lattice and thermal mismatch of the materials. It is even greater for e-mode designs, Imec said.
Imec was able to demonstrate the GaN-on-Si e-mode MOSHEMT that reaches a record of 27.8 dBm (1 W/mm) output power and 66% power-added efficiency (PAE) at 13 GHz and 5 V. The result was obtained in a single device with an eight-finger gate layout
“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.”
