New driving parameters for diamond deposition reactors: pulsed mode versus continuous mode

Experimental investigation and modeling of pulsed H2/CH4 plasmas used for diamond deposition are presented. Two plasma configurations are studied : a 2.45 GHz microwave cavity configuration and a 915 MHz surface-wave configuration. Time-resolved measurements of the gas temperature determined from the Doppler broadening of the Balmer Ha line, of the H-atom relative density and of the discharge volume (Vpl) are reported. The experimental time-variations of the gas temperature are characterized by a sharp increase at the beginning of the pulse (t < 250 µs) and a decrease down to a stable value a...