Chemical properties of a-Si:H interface layers on oxide-covered and hydrogen-terminated silicon

Book · Tue Dec 31 04:00:00 EST 1996

OSTI ID:527671

Knobloch, J; Hess, P ^[1]

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1. Univ. of Heidelberg (Germany). Inst. of Physical Chemistry

High quality a-Si:H films were deposited by pulsed VUV (157 nm) laser CVD, allowing digital control of the deposition process. Nucleation and growth on native oxide-covered Si (100) and on H-terminated Si (111) surfaces were studied in situ by FTIR transmission spectroscopy with sub-monolayer sensitivity. The film thickness was monitored simultaneously using a quartz crystal microbalance (QCM) with comparable resolution. The in situ spectra reveal that the nature of the substrate surface significantly influences the hydrogen bonding configuration in the interface region. In both cases the assumed cluster growth during the initial stage is characterized by a band around 2100 cm{sup {minus}1}, which is assigned to SiH{sub x} (x = 1 {minus} 3) surface modes. This band broadens until the clusters coalesce and band saturation occurs. At this time a second band starts to grow at 2,000 cm{sup {minus}1}, which is attributed to bulk SiH bonds. Difference spectra calculated for layers at different depths with definite thickness and the deconvolution of the broad feature observed during the very first stage of film growth indicate the existence of a hydrogen-rich layer at the substrate surface whose composition and thickness depend on the properties of the substrate surface.

• OSTI ID: 527671
• Report Number(s): CONF-960401--; ISBN 1-55899-323-1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL VAPOR DEPOSITION
EXPERIMENTAL DATA
FOURIER TRANSFORM SPECTROMETERS
IN-SITU PROCESSING
INTERFACES
LASERS
MICROBALANCES
NUCLEATION
PASSIVATION
ROUGHNESS
SILICON
THIN FILMS