£600k+ · Other round · Energy · UK
UK semiconductor-materials startup HexSeed Technology has raised more than £600,000 in early funding, led by climate venture builder Carbon13, with participation from the Net Zero Technology Centre and Vento Ventures. The financing was announced on 21 August 2026 by UKTN and in the company's official release. HexSeed says the cumulative investment also unlocks a provisionally awarded Innovate UK Partnership Grant; the grant amount was not disclosed.
HexSeed is developing a low-temperature microwave-plasma process that grows diamond coatings directly onto finished gallium-nitride power devices. GaN transistors can convert power more efficiently than silicon alternatives, but their heat is concentrated in small active regions. Conventional diamond growth runs at temperatures that would damage a completed device, so HexSeed's technical proposition is to deposit the thermally conductive layer after fabrication without destroying the chip.
Commercial proof starts on customer hardware
The funding will move the process from laboratory demonstration to working commercial GaN devices and support pilot customer engagements, initially in data-centre power-conversion hardware. That sequence matters: HexSeed has not claimed commercial deployment or published device-performance results. Its next proof point is whether the coating works repeatably on components that prospective customers already manufacture and qualify.
Applying the coating to finished devices could make adoption less disruptive than asking chipmakers to redesign an entire fabrication flow. It also creates a demanding commercial dependency. Semiconductor customers will need evidence on yield, reliability, lifetime and compatibility before they design the process into power modules. A successful lab result therefore opens the qualification process rather than completing it.
AI electricity demand sharpens the efficiency case
The timing gives that qualification work a clear customer problem. The International Energy Agency projects global data-centre electricity consumption to more than double to about 945 TWh by 2030, with AI the largest driver of the increase. HexSeed is targeting the conversion stage where electricity is conditioned for computing hardware, so better thermal management could allow GaN devices to operate at higher power density while reducing heat-related losses and wear.
The company was founded in late 2025 by CEO Mark Tandy, CTO Dr Leonardo Santoni and COO Dr Michael Glerum, and is working with University of Bristol researchers on the coating process. This capital buys a specific transition: from an advanced-materials concept to measured results on commercial devices. Pilot interest will matter, but the stronger milestone will be qualification data that turns a promising coating into a component process customers can adopt.
