The effect of uv light on ir absorption in chemically vapor deposited a-SiN[sub x]:H films

Conference · Wed Jan 01 00:00:00 EST 1992

OSTI ID:6906270

Seager, C H ^[1]; Kanicki, J ^[2]

---

1. Sandia National Labs., Albuquerque, NM (United States)
2. IBM Watson Research Center, Yorktown Heights, NY (United States). IBM Research Div.

We measured the optical absorption properties of Plasma Enhanced Chemically Vapor Deposited (PECVD) films of hydrogenated amorphous silicon nitride (a-SiN[sub x]:H) over the energy range from 0.54 to 2 eV using Photothermal Deflection Spectroscopy (PDS). The near-infrared absorption properties of these films measure the H bonded to Si or N as well as density of electronic gap states due to species like Si dangling bonds. Typical PDS spectra obtained on as-deposited films show a broad absorption tail with a large number of narrow absorption peaks. Nitride-related absorption was separated from that arising from the fused quartz substrates. In addition to the broad, featureless band tail, whose magnitude is quite sensitive to optical excitation with light above [approximately]3.9 eV, we observe a number of narrow absorption peaks which we identify as overtones of localized vibrational modes. Specifically, we see peaks at 0.82 and 1.20 eV which we identify as the 1st and second harmonics of N-H stretching vibrations, and several other peaks whose origins remain undetermined. Prolonged UV excitation produces no detectable change in these vibrational modes, although large changes are seen in the underlying absorption tail. This reinforces previous suggestions that photoinduced changes in these films do not arise from rearrangement of the bonded hydrogen.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6906270
• Report Number(s): SAND-92-1520C; CONF-921101-18; ON: DE93004502
• Resource Relation: Conference: 16. Material Research Society international symposium on the scientific basis for nuclear waste management fall meeting, Boston, MA (United States), 30 Nov - 5 Dec 1992
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
SILANES
ABSORPTION SPECTRA
SILICON NITRIDES
AMORPHOUS STATE
CHEMICAL VAPOR DEPOSITION
FILMS
OPTICAL PROPERTIES
VIBRATIONAL STATES
CHEMICAL COATING
DEPOSITION
ENERGY LEVELS
EXCITED STATES
HYDRIDES
HYDROGEN COMPOUNDS
NITRIDES
NITROGEN COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
SILICON COMPOUNDS
SPECTRA
SURFACE COATING
360204* - Ceramics
Cermets
& Refractories- Physical Properties