Optical dielectric function and infrared absorption of hydrogenated amorphous silicon nitride films: Experimental results and effective-medium-approximation analysis

Journal Article · Wed Aug 15 00:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.3666· OSTI ID:6521221

Yin, Z; Smith, F W ^[1]

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1. Department of Physics, City College of the City University of New York, New York, NY (USA)

The optical dielectric function {epsilon} (1.5--6.5 eV), ir absorption (400--4000 cm{sup {minus}1}), and film density have been measured for a series of hydrogenated amorphous silicon nitride ({ital a}-Si{sub {ital x}}N{sub {ital y}}H{sub {ital z}}) films deposited at 400 {degree}C via rf plasma-enhanced chemical vapor deposition for varying (NH{sub 3})/(SiH{sub 4}) ratios {ital R}. From a detailed analysis of the ir and density results, the concentrations of Si-N, N-H, Si-H, and Si-Si bonds and of Si, N, and H atoms have been obtained for the films studied. An effective-medium-approximation analysis of the measured {epsilon} based on the Si-centered tetrahedron model presented in the preceding paper has provided a more sensitive means of determining the concentration of Si-Si bonds in the films and has demonstrated that careful measurements of {epsilon}{sub 1} and {epsilon}{sub 2} can serve as a useful probe of the bonding in these alloys. Approximately 9{times}10{sup 20} Si-Si bonds/cm{sup 3} have been found in N-rich films which are close in composition to silicon diimide, Si(NH){sub 2}, and these Si-Si bonds have been found to have a significant influence on both the optical energy gap {ital E}{sub opt} and the refractive index {ital n} of the films. New results obtained from the ir absorption measurements include the identification of (1) a shoulder near 1030 cm{sup {minus}1} on the main 880-cm{sup {minus}1} Si-N({ital s}) band and (2) a weak absorption feature near 640 cm{sup {minus}1} which is not hydrogen related. It has been found that the N-rich diimidelike films prepared here have very low porosities and are thermally stable up to 700 {degree}C, properties which will be important for their future applications.

• DOE Contract Number: FG02-87ER45317
• OSTI ID: 6521221
• Journal Information: Physical Review, B: Condensed Matter; (USA), Vol. 42:6; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
SILICON NITRIDES
OPTICAL PROPERTIES
ABSORPTION SPECTRA
AMORPHOUS STATE
BINARY ALLOY SYSTEMS
CHEMICAL BONDS
DIELECTRIC PROPERTIES
EXPERIMENTAL DATA
FILMS
HYDROGENATION
INFRARED RADIATION
ALLOY SYSTEMS
CHEMICAL REACTIONS
DATA
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
INFORMATION
NITRIDES
NITROGEN COMPOUNDS
NUMERICAL DATA
PHYSICAL PROPERTIES
PNICTIDES
RADIATIONS
SILICON COMPOUNDS
SPECTRA
360602* - Other Materials- Structure & Phase Studies
360603 - Materials- Properties