Richard S. Vallery

Evolution of nanoscale pore structure in coordination polymers during thermal and chemical exposure revealed by positron annihilation.

[*] Prof. A. J. Matzger, Dr. A. G. Wong-Foy, J. K. Schnobrich Department of Chemistry, University of Michigan 930N. University St., Ann Arbor, MI 48109 (USA) E-mail: matzger@umich.edu Prof. D. W. Gidley, Dr. M. Liu, Dr. W. E. Frieze Department of Physics, University of Michigan 450 Church St. Ann Arbor, MI 48109 (USA) E-mail: gidley@umich.edu Prof. R. S. Vallery Department of Physics, Grand Valley State University 151 Padnos Hall, Allendale, MI 49401 (USA)

Pore Sealing by NH3 Plasma Treatment of Porous Low Dielectric Constant Films

Porous interlayer dielectric films with interconnected pores pose a serious challenge for their integration into next-generation microchips. The opening of interconnected pores in the surface region needs to be sealed to prevent intrusion of atomic layer deposition precursors used to create metal diffusion barriers. In this paper, we report the formation of a thin, nonporous surface layer on a porous methyl-silsesquioxane-based dielectric film by NH 3 plasma treatment. Depth-profiled beam positronium annihilation lifetime spectroscopy was applied to conveniently examine the formation of the dense layer. A nonporous surface layer was readily identified by the curtailment of positronium escape into vacuum through the surface. Among plasma treatments at temperatures ranging from 25 to 300°C for duration of 3-600 s, the best result was achieved at 300°C for 10 s. A very thin skin layer, ∼ 10 nm, could be formed with little damage to the bulk of the low-κ film. This thin skin layer further proved to improve the performance of Ta barriers for Cu diffusion. Chemical analysis, infrared spectroscopy, and sputtering secondary ion mass spectroscopy were also performed to examine how the plasma treatment altered the dielectric film.

Precision lifetime measurements of a single trapped ion with ultrafast laser pulses

We report precision measurements of the excited state lifetime of the

Characterization of fatigue-induced free volume changes in a bulk metallic glass using positron annihilation spectroscopy

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Assessment of the fatigue transformation zone in bulk metallic glasses using positron annihilation spectroscopy

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Revealing hidden pore structure in nanoporous thin films using positronium annihilation lifetime spectroscopy

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Deducing nanopore structure and growth mechanisms in porogen-templated silsesquioxane thin films

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The Intense Slow Positron Beam Facility at the NC State University PULSTAR Reactor

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