NITROGEN INDUCED INCREASE OF GROWTH-RATE IN CHEMICAL-VAPOR-DEPOSITIONOF DIAMOND

Polycrystalline diamond films have been grown by microwave assisted ch emical vapor deposition from methane/hydrogen gas mixtures. The additi on of small amounts of nitrogen with concentrations below 50 ppm to th e process gas was found to drastically increase the deposition rate de pending on the microwave power. At 4.2 kW microwave power a five times higher growth rate compared to nitrogen-free depositions was achieved . The optical transmission and thermal conductivity have been measured . The incorporation of small amounts of nitrogen does not degrade the infrared transmission of the samples; the thermal conductivity measure d at room temperature decreased only slightly from 20.5 to 18 W/(cm K) . (C) 1996 American Institute of Physics.