| Budget Amount *help |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥2,000,000 (Direct Cost: ¥2,000,000)
|
|---|
| Research Abstract |
Flattened diamond crystals synthesized by CVD have very flat surfaces, good crystallinity and contain defects in low density. If large flattened diamond crystals (e.g.1 mm diameter) can be synthesized, many application, for example, semiconductor substrates and heat sinks, are expected. In this report, the author describes an investigation of the most suitable synthesis condition and growth mechanism of the flattened diamond crystals.
Growth experiment
The substrate temperature in the nucleation stage plays an important in the yield of the flattened diamond crystals. When the substrate temperature is kept at 500 during the nucleation stage, the yield of flattened diamond crystals is higher than when the substrate temperature is kept constant at 750 . The copper substrate is the most suitable material for the synthesis of the flattened diamond crystals. Based on SEM observations, it was determined that approximately 90% of the diamond crystals show flattened morphology under optimum conditions.
Growth mechanism
In the first stage of crystal growth, texture growth nucleation occurred with {111}-oriented surfaces, and twin boundaries parallel to {111} and thus to the substrate surface appear. Due to the presence of re-entrant corners along multiple twin-boundaries, the pre-ferential growth of side faces takes place in six directions, leading to the formation of flattened diamond crystals.
|
