COMBINED EFFECT OF NITROGEN AND PULSED MICROWAVE PLASMA ON DIAMOND GROWTH

Deposition of diamond layers from a CH4-H-2 microwave discharge operat ing in pulse mode was achieved. The resulting diamond layers showed le ss graphite contamination as compared with that obtained in continuous discharge. Furthermore the addition of nitrogen to the discharge oper ating in this pulse mode was shown to further decrease the graphite co ntamination and to improve crystallisation due to reduction of seconda ry germination. However using nitrogen in the gas mixture resulted als o in a decrease in nucleation density and in discontinuous formation o f diamond layers. (C) 1997 Elsevier Science S.A.