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Title: Infrared absorption cross section of SiN x thin films

Abstract

At the molecular level, resonant coupling of infrared radiation with oscillations of the electric dipole moment determines the absorption cross section, $$σ$$. The parameter σ relates the bond density to the total integrated absorption. In this work, $$σ$$ was measured for the Si–N asymmetric stretch mode in SiNx thin films of varying composition and thickness. Thin films were deposited by low pressure chemical vapor deposition at 850 °C from mixtures of dichlorosilane and ammonia. σ for each film was determined from Fourier transform infrared spectroscopy and ellipsometric measurements. Increasing the silicon content from 0% to 25% volume fraction amorphous silicon led to increased optical absorption and a corresponding systematic increase in σ from 4.77 × 10–20 to 6.95 × 10–20 cm2, which is consistent with literature values. The authors believe that this trend is related to charge transfer induced structural changes in the basal SiNx tetrahedron as the volume fraction of amorphous silicon increases. Furthermore, experimental $$σ$$ values were used to calculate the effective dipole oscillating charge, q, for four films of varying composition. The authors find that q increases with increasing amorphous silicon content, indicating that compositional factors contribute to modulation of the Si–N dipole moment. Additionally, in themore » composition range investigated, the authors found that $$σ$$ agrees favorably with trends observed in films deposited by plasma enhanced chemical vapor deposition.« less

Authors:
 [1];  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1601442
Report Number(s):
SAND-2019-10850J
Journal ID: ISSN 0734-2101; 679381
Grant/Contract Number:  
AC04-94AL85000; NA0003525
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Vacuum Science and Technology A
Additional Journal Information:
Journal Volume: 38; Journal Issue: 1; Journal ID: ISSN 0734-2101
Publisher:
American Vacuum Society / AIP
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

DiGregorio, Sara N., and Habermehl, Scott D. Infrared absorption cross section of SiN x thin films. United States: N. p., 2019. Web. doi:10.1116/1.5128359.
DiGregorio, Sara N., & Habermehl, Scott D. Infrared absorption cross section of SiN x thin films. United States. https://doi.org/10.1116/1.5128359
DiGregorio, Sara N., and Habermehl, Scott D. 2019. "Infrared absorption cross section of SiN x thin films". United States. https://doi.org/10.1116/1.5128359. https://www.osti.gov/servlets/purl/1601442.
@article{osti_1601442,
title = {Infrared absorption cross section of SiN x thin films},
author = {DiGregorio, Sara N. and Habermehl, Scott D.},
abstractNote = {At the molecular level, resonant coupling of infrared radiation with oscillations of the electric dipole moment determines the absorption cross section, $σ$. The parameter σ relates the bond density to the total integrated absorption. In this work, $σ$ was measured for the Si–N asymmetric stretch mode in SiNx thin films of varying composition and thickness. Thin films were deposited by low pressure chemical vapor deposition at 850 °C from mixtures of dichlorosilane and ammonia. σ for each film was determined from Fourier transform infrared spectroscopy and ellipsometric measurements. Increasing the silicon content from 0% to 25% volume fraction amorphous silicon led to increased optical absorption and a corresponding systematic increase in σ from 4.77 × 10–20 to 6.95 × 10–20 cm2, which is consistent with literature values. The authors believe that this trend is related to charge transfer induced structural changes in the basal SiNx tetrahedron as the volume fraction of amorphous silicon increases. Furthermore, experimental $σ$ values were used to calculate the effective dipole oscillating charge, q, for four films of varying composition. The authors find that q increases with increasing amorphous silicon content, indicating that compositional factors contribute to modulation of the Si–N dipole moment. Additionally, in the composition range investigated, the authors found that $σ$ agrees favorably with trends observed in films deposited by plasma enhanced chemical vapor deposition.},
doi = {10.1116/1.5128359},
url = {https://www.osti.gov/biblio/1601442}, journal = {Journal of Vacuum Science and Technology A},
issn = {0734-2101},
number = 1,
volume = 38,
place = {United States},
year = {2019},
month = {12}
}