SAN FRANCISCO – November 06, 2026 -- Diamond Foundry Inc. has produced the first single-crystal diamond measuring 200 millimeters in diameter, a size the company says brings the material to semiconductor wafer scale.
The company unveiled the D200mm crystal alongside a video keynote by CEO Martin Roscheisen at CarbonSemi 2026 in Ningbo, China. Diamond Foundry states the crystal is neither an assembly of smaller diamond pieces nor a polycrystalline wafer. The first crystal is shown as grown and unpolished.
Crystal size has been the main constraint on diamond in electronics
Diamond Foundry says diamond combines the highest thermal conductivity with mechanical strength, electrical insulation and optical properties. Its use in advanced technology has been limited by crystal size. Natural diamond is constrained by geology, and conventional lab-grown diamond has historically been limited to relatively small crystals, according to the company.
Thermal management is the application the company stresses. Modern AI processors concentrate large amounts of power in microscopic regions of silicon. Diamond can spread that heat at the material level, the company says, opening options for chip architectures, power densities, reliability and cooling.
Two researchers' 25-year effort fed a program of hundreds of staff
Roscheisen credited Stefan Gsell and Martin Fischer, who began work on scaling single-crystal diamond 25 years ago. Their work became part of an effort involving hundreds of Diamond Foundry engineers, scientists and technicians. It spans plasma generation, growth chemistry, reactor architecture, metrology and automation.
Roscheisen said the result "makes D300mm predictable as well." The company provided no timeline or production data for either size.
Diamond Foundry is scaling chip substrates under a $2.77B Spanish project
The company is scaling volume production of chip substrates through a $2.77B EU Chips Act project in Spain.