PROCESS AND APPARATUS FOR WATER-BASED PLASMA CVD OF DIAMOND FILMS

摘要

A chemical vapor deposition (CVD) process and apparatus for growing diamond films are taught, using gas mixture, specifically precursors providing carbon species and etchant species that remove graphite. First, feedstock gas (13, 14) enters a conversion zone (low density plasma (17)). Second, by-products (H2, CO, C2, H2, no O2, some residual water) from the conversion zone proceed to an atomization zone (high density plasma (16)) producing diamond. The feedstock gas mixture may include at least 20 % water, which provides the etchant species, is reacted with an alcohol, which provides the carbon precursor, at 55-1100 °C and 0.1 to 100 Torr, preferably with an organic acid (acetic acid) which contributes etchant species. Oxygen formerly on H2O is transferred to CO. Hence, an etchant species (H2O, OH, O) is replaced in the reactor by CO, a growth species and prevents undesirable consumption of diamond. In the apparatus, gas cannot circumvent the conversion zone and the atomization zone produces the necessary atomic hydrogen for diamond growth.