Diamond Foundry has demonstrated a continuous 200mm single-crystal diamond specimen, advancing its development of synthetic diamond materials intended for semiconductor thermal management and other demanding technology applications.
The company presented the specimen at CarbonSemi 2026 in Ningbo, China, with chief executive Martin Roscheisen describing the development during a video keynote. Diamond Foundry published details of the achievement on 5 November.
Designated D200mm, the specimen measures 200 millimetres in diameter and consists of a single continuous crystal rather than a structure assembled from smaller diamond pieces. The company describes it as the first single-crystal diamond grown at this diameter.
The material has been shown in its as-grown, unpolished condition. Diamond Foundry has not published manufacturing yield figures, detailed defect measurements, processing specifications or a confirmed timetable for supplying commercially qualified 200mm diamond wafers.
Producing a larger continuous crystal addresses one of the longstanding constraints associated with synthetic diamond manufacturing. Although diamond has material properties attractive for advanced electronics, the limited dimensions of available single crystals have restricted the development of larger substrates and other components.
Single-crystal materials contain a continuous crystal lattice rather than the multiple grains characteristic of polycrystalline structures. Grain boundaries can influence the behaviour of a material, making the distinction important where specific electrical, thermal or mechanical properties are required.
Diamond’s high thermal conductivity is one reason semiconductor manufacturers and research organisations are investigating its use. Modern electronic devices can concentrate substantial power dissipation within small regions, creating high local temperatures that must be managed through the surrounding package and cooling equipment.
Heat generated in a semiconductor device must travel through a sequence of materials before reaching a heat sink or another part of the cooling system. The thermal resistance of each layer and interface contributes to the temperature difference between the active device and its surroundings.
A material with high thermal conductivity can help transfer heat away from concentrated sources. Diamond may therefore be useful as a heat spreader within selected semiconductor packages, provided the material is incorporated into an appropriate thermal design.
Its bulk thermal conductivity does not determine the performance of the completed package on its own. The thickness, geometry, attachment method and condition of the interfaces between diamond and neighbouring materials can all influence heat transfer.
Even a highly conductive layer may provide a limited benefit if the heat encounters substantial resistance where two materials meet. Bonding quality and surface preparation are therefore important engineering considerations in applications using diamond for thermal management.
The D200mm demonstration concerns the growth of the crystal, not the completed manufacture of a device-ready thermal interface. Additional processing and qualification would be needed before the material could be incorporated routinely into commercial semiconductor production.
Crystal growth at larger dimensions creates demanding requirements for the equipment used to maintain suitable conditions during manufacture. Diamond Foundry identifies advances in plasma generation, growth chemistry, reactor design, thermal management, measurement and automation as contributing to the result.
Growth conditions must be controlled across the developing crystal. Variations in temperature, chemistry or other operating parameters can affect the structure and properties of the resulting material, while the equipment must maintain suitable conditions as growth progresses.
Scaling a process also requires attention to consistency. A successful specimen demonstrates that a particular result can be achieved, but commercial manufacturing depends on reproducing material with the required characteristics over successive production cycles.
Defects are an important part of that assessment. Crystal imperfections can affect material behaviour, and the acceptable level depends on whether the diamond is intended for thermal management, electronic devices, optical equipment or another application.
Finished substrates may also require cutting, lapping, polishing and other processing to achieve the dimensions and surface condition needed by downstream manufacturing equipment. The requirements vary according to the material’s final application.
Diamond Foundry has not provided evidence that the demonstrated specimen has completed those stages or satisfied a published commercial wafer specification. Its 200mm diameter is therefore a significant dimensional result rather than proof of compatibility with an established semiconductor production line.
Conventional semiconductor manufacturing uses wafers produced to closely controlled dimensional and surface specifications. These allow automated equipment to handle the substrates and perform repeated manufacturing operations under defined conditions.
A 200mm diameter is an established size in semiconductor fabrication, particularly for a range of analogue, power and specialised products. Diamond Foundry’s achievement brings the size of its crystal closer to that manufacturing format.
Matching the diameter does not mean that existing equipment can process the material without modification. Diamond has different mechanical, thermal and surface characteristics from silicon, and its behaviour during fabrication must be considered for each intended operation.
Substrate compatibility also depends on thickness, flatness, surface condition and how the material responds to the processing techniques used. Handling a 200mm crystal is consequently a separate engineering question from manufacturing semiconductor devices or package components on it.
Diamond Foundry describes the milestone as the outcome of a development programme extending over more than a decade. The effort combines expertise acquired through its 2022 purchase of Augsburg Diamond Technology with the company’s existing crystal growth equipment and manufacturing operations.
The acquired research included work by Stefan Gsell and Martin Fischer, who had pursued the challenge of growing larger single-crystal diamonds over an extended period.
Roscheisen said the result reflected contributions from researchers and manufacturing personnel across the programme.
“Hundreds of DF engineers, scientists, and technicians contributed to us getting here,” he said.
The company intends to develop single-crystal diamond for semiconductor, optical and other advanced technology applications. These fields make use of different properties of the material and may require substantially different processing and qualification arrangements.
Diamond’s wide bandgap and other electronic characteristics have also prompted research into devices intended for demanding electrical operating conditions. Commercial electronic applications require further control of material characteristics and device fabrication processes beyond the ability to grow a large crystal.
The D200mm specimen does not demonstrate a commercial diamond semiconductor device, nor has the company announced electrical performance results from devices manufactured using the new material.
Diamond Foundry has identified 300mm crystal growth as a longer-term objective. Roscheisen has expressed confidence that the latest development supports progress towards that diameter, but no completed 300mm specimen or qualified production process has been announced.
The next manufacturing questions concern the consistency of the growth process, the usable area of the material, defect control and the ability to prepare suitable surfaces for downstream applications. Production cost will also influence whether diamond can be used economically in the intended equipment.
The company has not disclosed the cost per specimen, processing yield or expected price of a qualified 200mm substrate. Those details will be necessary to assess the industrial economics of the technology alongside its material performance.
The demonstrated crystal establishes a larger continuous growth scale for synthetic diamond. Subsequent processing, material characterisation and repeatable manufacturing results will determine how the development can be translated into commercially available components for semiconductor thermal management and other applications.
