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Imec Announces Silicon Photonics R&D Breakthrough

Products of the Month R&D Breakthrough

Imec, a globally renowned research and innovation hub in nanoelectronics and digital technologies, has announced a significant breakthrough in silicon photonics. The organization has successfully demonstrated electrically driven GaAs-based multi-quantum-well nano-ridge laser diodes that have been fully, monolithically fabricated on 300mm silicon wafers in its CMOS pilot prototyping line.

Achieving room-temperature continuous-wave lasing with threshold currents as low as 5 mA and output powers exceeding 1 mW, the results, as published in a recent edition of Nature, demonstrate the potential for direct epitaxial growth of high-quality III-V materials on silicon. This breakthrough provides a pathway to developing scalable, cost-effective, high-performance optical devices for applications in data communications, machine learning, and artificial intelligence.


Addressing Key Barriers 

Purely decorative image appearing in an article blog post on Photonics Industry Monthly entitled Imec Announces R&D Breakthrough in Silicon Photonics
A 300mm silicon wafer featuring thousands of GaAs devices, including a close-up of multiple dies and a scanning electron micrograph of a GaAs nano-ridge after epitaxial growth. (Photo courtesy of Imec.)

A lack of highly scalable, native CMOS-compatible light sources has been a critical barrier to the widespread adoption of silicon photonics. Traditional approaches—such as hybrid or heterogeneous integration solutions like flip-chip bonding, micro-transfer printing, and die-to-wafer bonding—are costly, complex, and resource-intensive. These processes involve expensive III-V substrates, often discarded after processing, raising concerns about sustainability and resource efficiency.

Imec’s R&D breakthrough in achieving the direct epitaxial growth of III-V optical gain materials selectively on large-size silicon photonics wafers provides a sustainable and efficient alternative.

The mismatch in crystal lattice parameters and thermal expansion coefficients between III-V and Si materials has historically resulted in crystal misfit defects that degrade laser performance and reliability. Selective-area growth (SAG), combined with aspect-ratio trapping (ART), significantly reduces defects in III-V materials integrated on silicon by confining misfit dislocations within narrow trenches etched in a dielectric mask.

“Over the past years, imec has pioneered nano-ridge engineering, a technique that builds on SAG and ART to grow low-defectivity III-V nano-ridges outside the trenches. This approach not only further reduces defects but also enables precise control over material dimensions and composition. Our optimized nano-ridge structures typically feature threading dislocation densities well below 10⁵ cm⁻². Now, imec exploited the III-V nano-ridge engineering concept to demonstrate the first full wafer-scale fabrication of electrically pumped GaAs-based lasers on standard 300mm silicon wafers, entirely within a CMOS pilot manufacturing line,” says Bernardette Kunert, scientific director at imec.


Achieving High-Performance GaAs-Based Nano-Ridge Lasers

Leveraging low-defectivity GaAs nano-ridge structures, the lasers integrate InGaAs MQWs as the optical gain region, embedded in an in-situ doped p-i-n diode and passivated with an InGaP capping layer. Achieving room-temperature, continuous-wave operation with electrical injection marks a major advancement, overcoming challenges in current delivery and interface engineering.

The devices show lasing at approximately 1020 nm with threshold currents as low as 5 mA, slope efficiencies up to 0.5 W/A, and optical powers reaching 1.75 mW. These achievements showcase a scalable pathway for high-performance silicon-integrated light sources.


A Scalable Pathway for Future Applications

“The cost-effective integration of high-quality III-V gain materials on large-diameter Si wafers is a key enabler for next-generation silicon photonics applications. These exciting nano-ridge laser results represent a significant milestone in using direct epitaxial growth for monolithic III-V integration,” states Joris Van Campenhout, fellow silicon photonics and director of the industry-affiliation R&D program on Optical I/O at imec.

Van Campenhout also emphasized that this work is part of imec’s larger mission to advance III-V integration processes toward higher technological readiness—from hybrid techniques like flip-chip bonding to direct epitaxial growth for advanced monolithic integration.


About Imec

Imec is a world-leading research and innovation center specializing in nanoelectronics and digital technologies. Headquartered in Leuven, Belgium, with research sites across Europe, the U.S., and Asia, imec collaborates with global leaders in the semiconductor and technology industries. The organization’s cutting-edge R&D spans domains including advanced semiconductor scaling, silicon photonics, artificial intelligence, and beyond 5G communications.

In 2023, imec reported €941 million in revenue, employing over 5,500 researchers and leveraging advanced facilities such as its CMOS pilot manufacturing line. Imec continues to drive innovation across industries, including health, mobility, and sustainable energy.

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Source/Photo Credit:Imec


(Editor’s Note: Imec is a registered trademark for the activities of Imec International and its affiliated entities. All trademarks mentioned in this article, including company names, product names, and logos, are the property of their respective owners. Use of these trademarks is for informational purposes only and does not imply any endorsement.)


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