Single crystal diamond is grown by microwave plasma CVD on single crystal substrate, seed. EDP has already developed as large single crystal as 10x10mm single crystal, and can fabricate the same size crystal by using of lift off procedure. Seeds may recycle and the cost of production is less expensive.
Advantage of our single crystal
- 1. Large and pure single crystal diamond made by microwave plasma CVD method
- 2. Fabricating of planner crystal by lift off procedure using of ion implantation
- 3. Laterally jointing two or more single crystal, called as mosaic crystal for fabricating large wafer
Process flow in EDP
- Realistic fabrication procedure of large substrate
- As current size of single crystal diamond is limited, large plate or substrate may be fabricated jointing of two or more single crystals laterally. Jointing with fine boundary is successfully obtained by using of two or more single crystals lifted off from the same seed. These crystals have the same orientation and the same growth manner. The result of jointing is show in the picture as you cannot identify where is boundary. We call this jointed crystals as Mosaic crystal. The maximum size of mosaic crystal is 25x25mm and we are planning to develop 2inch wafer by this method for utilizing in diamond device fabrication.
Fabrication procedure of large mosaic crystal
- Lift off procedure contribute large mosaic crystal and the boundaries are mostly invisible.
- We call large plate binding 2 or more crystals as "mosaic crystal", which is simular as "tile". Over growing of 2 or more single crystal, which crystal orientation are the same as(100), make jointed crystals. However, the interface could be significant boundary, looks black, using crystals having different growth history, method or lot. On contrast, lifting off 2 or more crystals from the same seed by our procedure, those crystal are brothers, twin, triplet etc. Placing such 2 or more crystals side by side and perform over growth on them. This procedure results large mosaic plate with very fine boundaries, mostly invisible. EDP was commercialized 1 inch wafer, 25x25mm and plans to develop 2 inch wafer which would be promising material for device application of diamond.
- Pure and high crystalinity promise to realize novel applications. Although the color is brownish, high hardness, high thermal conductivity, etc are guranteed.
- Diamond have superior characteristics and can be applied in various field. Cutting tool, optical parts, heat sinks etc. Even semiconducting device is the candidate application.