Diamond Foundry shows a 200 mm diamond crystal before polishing
At 200 mm across, the single crystal Diamond Foundry showed in November is twice the diameter of the one it reported in 2023. That gives four times the nominal area for two full circles, before any material is removed. The company showed the crystal unpolished, so the photographs capture how far the growth process got and leave the usable diameter after finishing open. [1][2][3]
The path to that diameter goes back at least to 2017, when Stefan Gsell and Martin Fischer helped publish a paper on growing a roughly 90 mm diamond. Their group used a microwave plasma and began the growth on iridium. Ion bombardment helped aligned regions of diamond form and spread across the surface until they joined. Diamond Foundry says it brought that research expertise in-house when it bought Augsburg Diamond Technology in 2022, although it has not said which details of the earlier process survived the move to 200 mm. [1][4]
Growth leaves a separate problem at the polishing stage: high spots have to come down to the required thickness, and the edge may need trimming before the material can go through a wafer process. A finished thickness map would show how uniform the material is after those steps.
Even if the thickness is uniform, defects can be concentrated in one part of a single crystal. A defect map would show how much of the wafer meets the requirements of a given device process and where that area lies.
Diamond Foundry’s announcement provides neither map and gives no finished wafer specification or yield from repeated runs. Its earlier result provides a comparison for the growth milestone; the company has yet to publish the equivalent comparison for finished wafers. [1][2][3]
