Diamond Foundry grows first 200mm single-crystal diamond wafer

Diamond Foundry says it has grown the first-ever D200mm single-crystal diamond — 200 millimeters across — a scale the San Francisco company calls a milestone for manufacturing diamond as a semiconductor-relevant material. CEO Martin Roscheisen unveiled the achievement in a keynote at CarbonSemi 2026 in Ningbo, China. “This is one of those milestones that once seemed almost impossible,” he said, crediting hundreds of Diamond Foundry engineers, scientists and technicians.

The breakthrough traces back 25 years, to work by Stefan Gsell and Martin Fischer on scaling single-crystal diamond, which Roscheisen says required advances across plasma generation, growth chemistry, reactor design, crystal engineering, thermal management and manufacturing. Diamond’s combination of high thermal conductivity, mechanical strength, electrical insulation and optical properties has long made it attractive for advanced technology, but crystal size — limited both in natural stones and in earlier lab-grown diamond — had kept it from reaching wafer scale, the way silicon did for electronics.

Diamond Foundry argues the limitation matters more now because modern AI processors concentrate large amounts of power into tiny areas of silicon, and diamond’s thermal conductivity could help spread that heat, opening possibilities for new chip architectures, power densities and cooling approaches. The company, which describes itself as the top producer of single-crystal diamond worldwide, is also building volume production of chip substrates through a $2.77 billion EU Chips Act project in Spain.

Diamond Foundry frames the D200mm crystal — shown as-grown and unpolished — as a starting point rather than an endpoint, and says the techniques behind it also make a future D300mm crystal achievable.

Why it matters

If Diamond Foundry can manufacture single-crystal diamond at wafer scale reliably, it adds a new thermal-management option for chipmakers racing to cool increasingly power-dense AI processors.