GaN-on-Silicon HEMTs for Tomorrow's Handsets?

Why It Matters

By delivering both high efficiency and low noise on a silicon platform, these GaN HEMTs could shrink RF front‑end size, cut component costs and accelerate the rollout of mmWave 5G/6G smartphones. Their CMOS‑compatible process also opens the door to fully integrated transmit/receive modules, a key step toward higher‑data‑rate mobile networks.

Key Takeaways

• GaN-on-silicon HEMTs achieve 62% power‑added efficiency at 10 V.
• Cut‑off frequency 100 GHz, fmax 254 GHz for 100 nm gate.
• Noise figure below 1.4 dB across 10‑40 GHz band.
• Process compatible with 300 mm CMOS lines, enabling low‑cost mass production.

Pulse Analysis

The mobile‑phone market is racing toward millimetre‑wave 5G and emerging 6G standards, which demand wider bandwidths and higher frequencies. Traditionally, RF front‑ends have relied on GaAs heterojunction bipolar transistors (HBTs) for their linearity and noise performance, but GaAs suffers from lower power density and higher manufacturing costs. Gallium nitride (GaN) offers a wider bandgap, higher breakdown voltage, and superior thermal handling, making it an attractive alternative—especially when integrated onto silicon, the workhorse of the semiconductor industry.

The A*STAR‑NTU‑Soitec team’s recent results showcase a mature silicon‑based GaN HEMT platform that delivers a rare combination of metrics: a power‑added efficiency of 62.3 % at a modest 10 V drain bias, an output power density of 1.19 W mm⁻¹, and a sub‑1.4 dB noise figure across the 10‑40 GHz range. With f_T of 100 GHz and f_max of 254 GHz, the devices meet the frequency demands of upcoming mmWave bands while maintaining linear gain of 11.1 dB. The use of a 100 nm gate length and a T‑shaped gate architecture also suppresses short‑channel effects, ensuring stable performance in compact, high‑frequency modules.

Beyond raw performance, the true breakthrough lies in the process compatibility. Fabricating these HEMTs on 300 mm silicon wafers aligns with existing CMOS fabs, enabling economies of scale and reducing per‑unit cost—a critical factor for mass‑market smartphones. The researchers envision a monolithic transmit/receive (TRX) module that integrates low‑noise amplifiers, power amplifiers, and RF switches on a single chip, slashing parasitic losses and board‑level complexity. As the industry pushes toward higher data rates and more integrated designs, GaN‑on‑silicon HEMTs could become the cornerstone of next‑generation mobile RF front‑ends, accelerating the transition to truly ubiquitous high‑speed connectivity.