Plasma characterisation in PECVD deposition of diamond

The focus of the initial work was the determination of the hydrogen atom density in the plasma since H atoms are thought to be of importance in determining the diamond film quality. The film quality was assessed by an in situ measurement of the refractive index of the depositing films. The absolute atomic hydrogen fraction in the plasma was measured using a two photon LIF technique. These measurements were then used to assess the possibility of using a combination of electrostatic probe and emission measurements to determine dissociation rates in molecular gas plasmas. The PECVD system had a single 13.56 MHz driven electrode with the metal vacuum vessel acting as the grounded electrode. The operating gas was predominately hydrogen with small (<5%) percentages of C2H2 added