Vibrational Properties of Amorphous Alloys

Lucovsky, G.; Pollard, W. B.

doi:10.1007/3540128077_7

Cited by 34 publications

(10 citation statements)

References 58 publications

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“…Studies by Hurwitz et al . have also reported the methyl stretching frequencies in liquid-phase synthesized poly(methylsilane) films as 2894 and 2956 cm -1 , , and studies of methyl-containing a-SiC:H films give similar values. ,, The frequencies in each of these systems are very close to those observed in the deposited a-SiC:H thin film.…”

Section: Resultsmentioning

confidence: 57%

“…This feature occurs at the frequency of Si-H stretching modes and is assigned to a mix of silicon mono-, di-, and trihydride groups based on comparison with literature values for both amorphous and singlecrystalline silicon: mono-(2000-2090 cm -1 ), di-(2090-2120 cm -1 ), and trihydride (2140-2154 cm -1 ). [41][42][43][44][45][46][47][48][49][50] The material probed in Figure 2a is a stable film and can easily be distinguished from its methylsilane precursor. First, multilayers of methylsilane (deposited at 100 K without the filament) desorb molecularly without decomposition by 180 K while the thin film grown at 200 K with the filament on is stable to 550 K. Furthermore, the infrared spectrum of the film differs significantly from that of methylsilane multilayers (see Figure 2b).…”

Section: Resultsmentioning

confidence: 99%

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Bonding and Thermal Reactivity in Thin a-SiC:H Films Grown by Methylsilane CVD

Lee

Bent

1997

J. Phys. Chem. B

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The bonding and thermal reactivity of thin a-SiC:H films have been studied and compared with that of methyl groups on single-crystalline Si and in thick polymer films. The films were deposited on silicon substrates at 200 K by hot-wire chemical vapor deposition (CVD) using methylsilane (CH3SiH3) as the precursor. The resulting films were probed by in situ multiple internal reflection−Fourier transform infrared (MIR−FTIR) spectroscopy, and the thermal decomposition products were measured by temperature-programmed reaction/desorption (TPR/D). According to MIR−FTIR measurements, hydrogen is present in the films in the form of mixed silicon hydride species (SiH, SiH2, and SiH3) and intact methyl groups. TPR/D and MIR−FTIR annealing studies following growth at 200 K indicate that the film is stable up to 550 K. Above 550 K, a number of thermal etching processes are observed, leading to silane and methylsilane evolution at 600 K, followed by the loss of methane and molecular hydrogen by 780 K. Annealing studies show that the SiH3 species are more reactive at thermal energies than are methyl groups. The stability of methyl groups and the silicon mono- and dihydride groups in the films largely parallels that observed on single-crystalline silicon, but more reaction pathways are available in the thin films. Mechanisms for the film growth and thermal decomposition are proposed.

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Section: Resultsmentioning

confidence: 57%

Section: Resultsmentioning

confidence: 99%

Bonding and Thermal Reactivity in Thin a-SiC:H Films Grown by Methylsilane CVD

Lee

Bent

1997

J. Phys. Chem. B

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“…In this study, we concentrate on a-Si:O 0.1 . Oxygen in amorphous silicon 8,9 forms a twofold bridging bond between two silicon atoms. As such, the oxygen atom resides in a site with a C 2v point-group symmetry.…”

Section: Introductionmentioning

confidence: 99%

Infrared transient grating and photon echo spectroscopy of oxygen vibrational modes in amorphous silicon thin films

et al. 2003

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We report on picosecond coherent transient spectroscopy on the asymmetric stretching mode in a-SiO 0.1 thin films using the Dutch free-electron laser FELIX. A fast 10-K lifetime of 2.8 ps is obtained using laser-induced transient grating spectroscopy. Its thermal behavior suggests relaxation into two accepting modes possibly via the symmetric stretch mode of the Si-O-Si complex. Two-pulse photon echo measurements reveal phase dynamics with both an excitation density and temperature dependence, suggesting the presence of nonequilibrium Si-Si phonons. The temperature-dependent component of the pure dephasing may be attributable to two-phonon elastic scattering. From the probe pulse diffraction efficiency, a value of the nonlinear refractive index has been determined to be n 2 ϭ3.73ϫ10 Ϫ3 cm 2 /GW.

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“…Oxygen in amorphous silicon [3] forms a two-fold bridging bond between two silicon atoms, residing in a site with a C 2v point group symmetry. In this work, we identify the fundamental vibrational relaxation processes of the asymmetric stretching vibration of the Si-O-Si complex in silicon suboxide thin layers.…”

Section: Introductionmentioning

confidence: 99%