Currently, our in-house crystal growth is done using the Czochralski method. We start with ultra-high purity source materials which are mixed and melted in a controlled atmosphere. Low dislocation density material is core drilled to provide high quality seed material. Through years of development, our growth department is able to provide material that is highly uniform and nearly defect free allowing Hoffman Materials to offer some of the highest performing materials in the world. Our research and development team is constantly working on the next generation materials which will supersede the current material properties/capabilities commercially available today.
Contrary to an amorphous material, a single crystal material exhibits unique properties relative to the inherent crystallographic planes. Therefore, it is critical that the desired orientation of the crystal is identified before processing the material. Through the use of double diffraction X-ray analysis of the crystalline material, we are able to provide parts cut to within 15 arc seconds of accuracy.
Due to the hardness and brittleness of many single crystal materials, special techniques must be used to cut them. Depending on the application and material, we use diamond and slurry wire saws, along with a variety of dicing saws, to cut and slice ceramics and single crystalline materials. Currently, we can process material up to 150 mm in diameter.
GRINDING AND LAPPING
Our precision grinding machines are used to shape crystalline materials into various geometries, with unique features, shapes and sizes. To reduce the thickness of a crystal, we use double-sided lapping machines which are capable of producing very thin pieces while maintaining flat and parallel surfaces. These machines can accommodate material up to 200 mm in diameter.
Hoffman Materials uses commercially available and specialized chemical etchants for the elimination of chips, sub-surface damage, and to relieve residual stress in the materials.
Annealing of crystalline or amorphous materials has been used for decades to treat and condition the materials. Depending on the atmosphere and temperature, heating of the material can cause internal bulk diffusion, surface diffusion or even thin film growth at the surface. Our furnaces are able to heat up to 1200°C with a range of controlled atmospheres and pressures. We have high precision gas flow controls integrated into our annealing systems for maintaining partial pressures of various gases.