Microstructure and hydrogen dynamics in a-Si{sub 1{minus}x}C{sub x}:H

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20107922

Shinar, R; Shinar, J; Williamson, D L; Mitra, S; Kavak, H; Dalal, V L

Small angle x-ray scattering (SAXS), IR spectroscopy, and deuterium secondary ion mass spectrometry (DSIMS) were used to study the microstructure and hydrogen dynamics of undoped and boron-doped rf-sputter-deposited (RFS) and electron cyclotron resonance (ECR)-deposited hydrogenated amorphous silicon carbides (a-Si{sub 1{minus}x}C{sub x}:H) with x {le} 19 at.%. The SAXS measurements indicated residual columnar-like features and roughly spherical nanovoids of total content C{sub nV} {le} 1.0 vol.%. The growth of C{sub nV} with annealing was due largely to an increase in the average nanovoid radius. It was noticeably smaller than in RFS a-Si:H films. The IR spectra demonstrated H transfer by annealing from mostly bulk-like Si-H groups to C-bonds. The H diffusion and its temperature dependence in undoped films resembled those of a-Si:H and were consistent with the SAXS and IR data. Suppression of long-range motion of most of the H atoms, consistent with increased C{sub nV}, was observed in B-doped ECR films. However, a small fraction of the H atoms appeared to undergo fast diffusion, reminiscent of the fast diffusion in doped a-Si:H. The results are consistent with impeded relaxation processes of the Si network, caused by the presence of C atoms, and H trapping at C-H bonds.

• Research Organization: Iowa State Univ., Ames, IA (US)
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 20107922
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMORPHOUS STATE
CHEMICAL BONDS
DIFFUSION
DOPED MATERIALS
HYDROGEN
HYDROGEN ADDITIONS
MICROSTRUCTURE
SILICON CARBIDES