Accelerating GaN-on-Silicon RF Power Amplification

Why It Matters

The breakthrough provides a low‑cost, high‑frequency power‑amplifier solution essential for deploying sub‑terahertz 6G networks and data‑center test equipment, accelerating the rollout of next‑generation connectivity.

Key Takeaways

• 0.67 W mm⁻¹ output at 123 GHz with 10 V bias.
• First GaN‑on‑silicon HEMT demonstrated beyond 100 GHz.
• Uses 5 nm AlN barrier and in‑situ SiN/Al₂O₃ passivation.
• f_T 112 GHz, f_max 205 GHz, 140 nm gate length.
• Low‑cost 300 mm silicon wafers cut RF power‑amp expenses.

Pulse Analysis

The race to 6G hinges on sub‑terahertz spectrum, where bandwidths of tens of gigahertz become feasible. Conventional power‑amplifier technologies such as InP HBTs and GaN‑on‑SiC HEMTs deliver the required performance but at high material and manufacturing costs. GaN‑on‑silicon, by contrast, combines the superior electron transport of III‑N heterostructures with the mature, low‑cost silicon wafer ecosystem, offering a pathway to affordable, high‑frequency RF solutions for data‑centers and telecom infrastructure.

In the latest study, a GaN‑on‑silicon HEMT fabricated on a 300 mm silicon substrate achieved a record 0.67 W mm⁻¹ output power at 123 GHz under a 10 V drain bias. The device’s epitaxial stack features a thin 5 nm AlN barrier that creates a high charge density, while an in‑situ SiN layer serves dual roles as surface passivation and gate dielectric, minimizing parasitic capacitance. With a 140 nm gate length, the transistor reaches a cutoff frequency of 112 GHz and a maximum oscillation frequency of 205 GHz, performance metrics that are competitive with GaN‑on‑SiC counterparts but at a fraction of the cost.

The implications extend beyond academic milestones. By demonstrating viable D‑band amplification on silicon, the research opens the door for mass‑produced, cost‑effective power amplifiers that can be integrated into the massive antenna arrays required for 6G’s terabit‑per‑second targets. Future work aims to reduce substrate RF loss, improve carrier mobility, and adopt advanced scaling techniques such as regrown contacts. As these refinements mature, manufacturers can expect a faster, cheaper path to sub‑terahertz RF components, reshaping the supply chain for next‑generation wireless and high‑precision radar systems.