Paper PS-ThM10
H₂/Ar and D₂/Ar Plasma Interactions with a-C:H Surfaces: A Detailed Study of Modified Layer Formation and Erosion

Thursday, October 21, 2010, 11:00 am, Room Aztec

The interaction of H₂ gas discharges with carbon-based materials has been of sustained interest in many technological fields. In this work we have used a well characterized, inductively coupled plasma system (ICP) to study the interaction of H₂/Ar and D₂/Ar discharges with hard a-C:H films. The erosion of a-C:H is monitored in real time by ellipsometry, optical emission spectroscopy and plasma properties are characterized by a Langmuir probe. Our experimental setup allows for varying the reactor geometry over a wide range by changing the plasma generation substrate distance. H₂/Ar and D₂/Ar plasma interaction with a-C:H were performed using low pressure (30 mTorr) 600 W 13.56 MHz RF inductive power plasma with different substrate bias voltages. Employing real-time ellipsometry, we were able to monitor the detailed kinetics of the formation of a 1-5 nm thick hydrogenated layer of lower density than the a-C:H substrate, followed by steady-state erosion. The influence of various plasma parameters on modified surface properties and erosion will be reported. We also will present real-time data which gives insight into the dynamic flux of carbon atoms into the plasma produced by erosion a-C:H for different conditions . The measurements of the modified surface layers are compared with “Stopping and Range of Ions in Matter (SRIM)” simulations for different conditions. The atomistic details of surface processes will also be be compared with molecular dynamics simulations of the UCB group.

We gratefully acknowledge support of this work by DOE’s Plasma Science Center for Predictive Control of Plasma Kinetics: Multi-phase and Bounded Systems (University of Michigan ).