DIAMOND SYNTHESIS FROM THE GAS-PHASE

This paper reviews structural features and some properties of diamond prepared from the gas phase. Single crystalline diamond films are grown on (100), (110) and (111) faces of diamond, and analyzed using secondary ion mass spectrometer. The results indicate that the contamination from a reaction vessel cannot be neglected, and that other impurities with concentration higher than that in natural diamond were not detected. The studies of texture of polycrystalline films deposited on Si by etching in oxidative plasma have revealed that the texture depends on the synthetic conditions. Single crystalline diamond particles and polycrystalline films have been characterized using optical techniques. The results indicate that single crystals prepared under optimum conditions have good crystalline quality similar to type IIa diamond, which is a high purity form in natural diamond. In contrast, the polycrystalline films grown under the same conditions have appreciable amounts of double-bond structures and strain.