Diamond Foundry Announces First-Ever D200mm Single-Crystal Diamond

Breakthrough culminates 25 years of scientific pursuit and establishes a new scale for single-crystal diamond

SAN FRANCISCO, Nov. 6, 2026 /PRNewswire/ -- Diamond Foundry Inc. today announced a major milestone in the history of materials technology: the creation of the first-ever D200mm single-crystal diamond, measuring 200 millimeters in diameter.

The achievement marks a fundamental step forward in humanity's ability to manufacture diamond as a technology material at semiconductor-relevant scale.

The announcement accompanies a keynote by Diamond Foundry CEO Martin Roscheisen, delivered by video at CarbonSemi 2026 in Ningbo, China. Watch the keynote: https://youtu.be/ae0XQBDlLMQ.

Diamond has long been recognized as an extraordinary material for technology. It combines the highest thermal conductivity with exceptional mechanical strength, electrical insulation, optical properties, and the potential for extreme electronic performance. Yet its use in advanced technology has been constrained by one basic limitation: size.

Diamond Foundry's D200mm breakthrough changes that.

Producing single-crystal diamond at D200mm scale required overcoming fundamental challenges in crystal growth, plasma physics, reactor engineering, materials science, process control, and manufacturing. The result is not an assembly of individual diamond pieces and not a polycrystalline diamond wafer. It is a single-crystal diamond at D200mm scale.

"This is one of those milestones that once seemed almost impossible," said Martin Roscheisen, CEO of Diamond Foundry Inc. "Hundreds of DF engineers, scientists, and technicians contributed to us getting here. It is the accumulated result of countless experiments, failures, inventions, rebuilt machines, and insights over more than a decade."

Roscheisen particularly recognized Stefan Gsell and Martin Fischer, whose work on scaling single-crystal diamond began 25 years ago.

"Stefan and Martin pursued this goal for 25 years," Roscheisen said. "There are very few examples in technology of someone sticking to a really hard scientific challenge with that level of perseverance. They kept going when the prevailing view was that single-crystal diamond simply could not be made at this scale. Today, the perseverance shows as the first-ever D200mm single-crystal diamond. And best of all, it makes D300mm predictable as well."

From Gemstone Dimensions to Semiconductor Dimensions

The semiconductor industry is built around the ability to manufacture extraordinary materials at wafer scale. Silicon's progression toward larger wafers transformed electronics by allowing increasingly sophisticated devices to be manufactured economically and repeatably.

Diamond has never had an equivalent scaling path.

Natural diamond is constrained by geology. Conventional lab-grown diamond has historically been constrained to relatively small crystal dimensions. Even as the extraordinary properties of diamond became increasingly relevant to high-power electronics, AI computing, optics, quantum systems, and other advanced technologies, crystal size remained a fundamental bottleneck.

The D200mm single-crystal diamond milestone demonstrates a path beyond that limitation.

For Diamond Foundry, the achievement is part of a broader effort to turn single-crystal diamond from a scarce material measured in gemstones into a tech-industrial semiconductor substrate manufactured at scale.

The implications are particularly significant as computing systems encounter increasingly severe thermal constraints. Modern AI processors concentrate enormous amounts of power into microscopic regions of silicon. Diamond's exceptional thermal conductivity can spread that heat at the material level, creating new possibilities for chip architectures, power densities, reliability, and cooling.

Twenty-Five Years of Perseverance

The D200mm achievement has roots extending well beyond Diamond Foundry itself.

For 25 years, Gsell and Fischer pursued the underlying scientific and engineering challenge of growing high-quality single-crystal diamond of scalable size. Their work ultimately became part of a much larger effort involving hundreds of people across Diamond Foundry.

The milestone reflects advances spanning plasma generation, growth chemistry, reactor architecture, crystal engineering, thermal management, metrology, automation, and manufacturing.

"Technology history is often written around the moment something finally works," Roscheisen said. "But that moment rests on the people who were willing to spend years — sometimes decades — making it work. This diamond exists because hundreds of people contributed, and because a few people refused to give up on the idea for 25 years."

A New Scale for Diamond

Diamond Foundry views D200mm not as an endpoint, but as the beginning of a new manufacturing era for diamond.

The company is developing single-crystal diamond for semiconductor and advanced-technology applications where diamond's combination of thermal, mechanical, electrical, and optical properties can enable performance beyond the limits of conventional materials.

The first D200mm crystal is shown as grown and unpolished — directly from the growth process.

For a material that nature forms only under extraordinary conditions deep inside the Earth, the significance is simple:

Single-crystal diamond has entered the wafer-scale era.

About Diamond Foundry Inc.

Diamond Foundry is the #1 producer of single-crystal diamond in the world. Founded in San Francisco, the company created the world's first diamond wafer and is scaling volume production of chip substrates with a $2.77B EU Chips Act project in Spain.

Media contact: Jeff Yurek, j@df.com

SOURCE Diamond Foundry