Page 21 - PEN eBook October 2025

SEMICONDUCTORS SEMICONDUCTORS

GaN COALESCE TECHNOLOGY This results in a radial expansion of the nanowires,
Hexagem’s patented GaN-on-Si technology thickening them until they eventually merge into a
significantly reduces crystal defects, cutting continuous film (Figure 1).
dislocation densities from the industry standard of
100 million/cm2 to a target of just 10 million/cm2. A 10-µm thickness is essential for vertical device
Their process is fully compatible with standard architectures, which improves power-handling
semiconductor manufacturing and addresses capability, efficiency, and device density. This positions
longstanding challenges in GaN growth on Hexagem as a potential disruptor to SiC in established
silicon—namely, defect formation, wafer cracking, and high-voltage applications, paving the way for
thermal mismatch. next-generation power electronics.

The technique involves selective epitaxial growth of
dislocation-free GaN nanowires on a patterned silicon
nitride buffer layer:

▶ Selective epitaxial growth: This
means growing GaN in specific
areas, using a substrate that
encourages the desired crystal REVOLUTIONARY InGaN FUNDING AND INVESTMENT
orientation. μLED TECHNOLOGY Hexagem has secured funding from various sources,
Beyond power electronics, Hexagem is pioneering including:
▶ Dislocation-free GaN nanowires: a breakthrough relaxed InGaN technology on silicon
Growing GaN as nanowires without wafers for the µLED market. This innovation targets ▶ Grants: Notably, the European Innovation Council
these defects improves its advanced red, green, and blue µLEDs for and the European Union have provided significant
structural and electronic quality. next-generation display applications. grant funding.

▶ Patterned silicon nitride buffer The advantages of Hexagem’s InGaN µLED technology ▶ Early-stage venture capital: Almi Invest has been
layer: This layer sits between silicon include: an early investor.
and GaN, helping control where
and how GaN grows. The pattern ▶ No lattice mismatch: The company’s approach ▶ Family office: GAP Technology Holding, focused
basically guides the placement of enables the formation of defect-free, on early-stage deep-tech companies with solid
nanowires. strain-relaxed InGaN platelets on silicon or IP portfolios, is also listed among its investors.
sapphire wafers. This critical advancement The company has been generating revenue and
Once these tiny, vertical nanowires allows for the precise tuning of indium has received multiple funding rounds since its
are formed, material is added to their composition, enabling efficient light emission inception.
sides (sidewall growth) so that they across the blue-to-red spectrum, a major
thicken, allowing them to coalesce hurdle in µLED production where full-color CHALLENGES AHEAD
into a thick, continuous GaN film with emission from a single material system is Like many startups, Hexagem faces several critical
improved structural integrity. This notoriously difficult. challenges, even with its bold vision and pioneering
enables the creation of crack-free technologies:
layers over 10 µm thick, far beyond the ▶ No etching defects: The technology directly
2–4 µm typical in the industry. produces sub-micron platelets, bypassing the ▶ Converting cutting-edge, lab-scale innovations
severe etch damage typically associated with into high-volume, commercially viable
GaN material is added in vapor form conventional LED pixel fabrication. manufacturing requires careful process
via metal-organic chemical-vapor optimization, cost control, and quality assurance.
deposition. During sidewall growth: ▶ Low wafer bow: Platelet growth on silicon
requires only a thin, low-quality GaN buffer ▶ With growing investment and established players
▶ Gallium adsorption atoms diffuse layer. This reduces manufacturing costs and in both the GaN and µLED markets, Hexagem
along the surface of the nanowire results in exceptionally low wafer must continuously innovate, differentiate, and
sidewalls. bow—essential for achieving high production build strategic partnerships to stay ahead.
yields.
▶ Nitrogen species (often active ▶ Last but not least, although initial capital has
nitrogen from plasma or ammonia) This novel approach offers a potentially simpler, been raised, ongoing investment will be vital to
react with the gallium to form GaN more cost-effective, and higher-yield manufacturing support R&D, scale manufacturing, and gain
on the side surfaces. pathway for full-color µLEDs, paving the way for their traction in highly competitive global markets.
widespread adoption in consumer electronics.

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