JJAP Conference Proceedings

JJAP Conf. Proc. 2, 011210 (2014) doi:10.7567/JJAPCP.2.011210

Subnanoporosity development in hydrocarbon-siliconoxide hybrid PECVD films elucidated by variable-energy positron annihilation

Kenji Ito1, Toshitaka Oka2, Chunqing He3, Yoshinori Kobayashi1

  1. 1National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan
  2. 2Institute for Excellence in Higher Education, Tohoku University, Sendai 980-8576, Japan
  3. 3Key Laboratory of Nuclear Solid State Physics Hubei Province, School of Physics and Technology, Wuhan University, Wuhan 430072, China
  • Received May 31, 2014
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Variable-energy positron annihilation spectroscopy was applied to the investigation of nanopore formation in hydrocarbon-siliconoxide hybrid films fabricated through plasma enhanced chemical vapor deposition. Positron lifetime and Fourier transform infrared absorption measurements revealed that the pore size increases from 0.4 to 0.8 nm in radius with increasing annealing temperature, illustrating that the formed pores are in the micropore range. Based on a one-dimensional diffusion model, the ortho-positronium diffusion length was estimated from the variation of the positron 3γ decay probability for the films annealed with various temperatures as a function of positron incident energy. The result suggested that the pore interconnectivity during the pore formation by annealing depends on the gradual decomposition of the carbonaceous component.

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