Using the imaging of radicals interacting with surfaces (IRIS) technique, the scattering of NH 2 on a variety of substrates has been measured during NH 3 , NH 3 /H 2 , and NH 3 /SiH 4 plasma processing. In most cases, NH 2 surface scattering was greater than unity for 300 K substrates, suggesting that NH 2 is produced through surface reactions. Removal of the charged species from the plasma molecular beam results in a significant decrease in scattered NH 2 signal. We have also measured velocity distributions and translational temperatures for NH 2 radicals scattering from 300 K substrates. Monte Carlo simulation methods were used to model spatially and temporally resolved profiles of scattered molecules. The model assumes an initial Gaussian distribution for radicals across the laser beam and calculates time-dependent changes in the profiles using Maxwell-Boltzmann distributions. For NH 2 radicals scattering from a 300 K Si substrate, the translational temperature, Θ Tsc , is 400 ( 30 K, significantly higher than the substrate temperature. Removal of the charged species from the plasma molecular beam results in a decrease in translational temperature for scattered NH 2 molecules, Θ Tsc ) 300 ( 30 K. This suggests ions are important in surface production of NH 2 and in the translational temperature of the scattered radicals.

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Pulsed plasma polymerization of benzaldehyde is used to produce thin films containing aldehyde functional groups. The effects of pulse peak power, pulse-on time, duty cycle, and monomer pressure on film composition, especially aldehyde functional groups, and surface polarity are examined. Film properties are determined using Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle measurements, and scanning electron microscopy (SEM). Analysis using these techniques shows retention of the aromatic structure occurs with the longest off times and smallest duty cycles while retention of the aldehyde group occurs only under plasma conditions that result in fragmentation of the aromatic ring, higher peak pulse power, and a relatively large duty cycle (20%).

The surface reactivity of the SiH radical was measured during plasma deposition of various silicon-based materials using the imaging of radicals interacting with surfaces (IRIS) method. In this technique, spatially resolved laser-induced fluorescence (LIF) is used to determine surface reaction probabilities, R or , of plasma species. For SiH, R is near unity, 0.96 ( 0.04, and shows no dependence on the gas mixture (SiH

The surface reactivity of CF2 radicals has been characterized during plasma processing of a variety of substrates using the imaging of radicals interacting with surfaces technique. The plasma molecular beam sources are 100% C2F6, 50/50 C2F6/H2, and 100% hexafluoropropylene oxide (HFPO) gas mixtures. Simulation of spatially resolved laser-induced fluorescence images in the 100% C2F6 system shows that CF2 has a scatter value, S, >1.0 with SiO2, polyimide and photoresist substrates. A scatter of >1.0 indicates that CF2 molecules are generated at the surface during plasma processing. With the 50/50 C2F6/H2 plasma, CF2 exhibits a lower scatter value (∼0.85) on Si, SiO2, and polyimide substrates. With the HFPO plasma source, S⩾1 for all continuous wave powers and substrates processed. Values of S∼0.8 are obtained for ion-free and pulsed plasmas, however, revealing ion collisions with the substrate play an important role in the surface generation of CF2. The radical-surface interaction data are correlated with data from surface characterization by x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy of the substrates. The key finding is that our results suggest the surface reactivity behavior of CF2 radicals correlates well to the overall plasma process (etching or deposition).