SINGLE-CRYSTAL DIAMOND DEPOSITION BY LAMINAR AND TURBULENT ACETYLENE-OXYGEN FLAMES

The homoepitaxial deposition of diamond layers on (111) and (001) type -IIa natural diamond substrates, by both laminar and turbulent acetyle ne-oxygen flames, is described. Using the same gas flows, temperatures , and supersaturations of 4%, a higher growth rate was obtained on a ( 001) substrate with a turbulent flame than with a laminar flame. Layer s grown at the same temperature on (111) substrates with a supersatura tion of 3% show no significant difference in growth rate. Due to the l arge differences in geometry between both types of flames it is not po ssible to relate the substrate positions in the acetylene feathers to each other and compare the growth results at any location. However, it is shown that the application of turbulent flames for single-crystal growth does not lead to a dramatic change in quality of the diamond as was previously reported in the literature. It is demonstrated by micr oscopic and spectroscopic techniques that the crystallographic orienta tion of the substrates, the deposition temperature, and the gas veloci ty all have a larger influence on the crystal morphology and impurity incorporation of the grown single crystals than the introduction of tu rbulence. (C) 1995 American Institute of Physics.