Environmental stability and cryogenic thermal cycling of low-temperature plasma-deposited silicon nitride thin films
- School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia 6009 (Australia)
Stress in low-temperature plasma-enhanced chemical vapor deposited silicon nitride (SiN{sub x}) thin films subject to cryogenic thermal cycling (100-323 K) has been measured. It is observed that the SiN{sub x} deposition temperature strongly influences the thin film characteristics. For films deposited between 200 and 300 deg. C, the thermal expansion coefficient is similar to that of silicon over the 180-323 K temperature range. The room temperature thermal expansion coefficient of SiN{sub x} films is found to decrease sublinearly from 5.2x10{sup -6} to 2.6x10{sup -6} K{sup -1} as the temperature of the deposition process is increased from 50 to 300 deg. C. The negative correlation between deposition temperature and thin film thermal expansion coefficient, and the positive correlation between deposition temperature and the thin film Young's modulus inferred from nanoindentation are postulated to be associated with the local bonding environment within the thin film. The stress state of SiN{sub x} films deposited above 150 deg. C is stable under atmospheric conditions, in contrast to SiN{sub x} films deposited below 100 deg. C, which under atmospheric storage conditions become more tensile with time due to oxidation. In addition, SiN{sub x} thin films deposited below 100 deg. C exhibit higher tensile stress values in vacuum than at atmospheric pressure, and vacuum annealing at 50 deg. C of films deposited below 100 deg. C introduces further tensile stress changes. These stress changes have been shown to be fully reversible upon reexposure to high purity nitrogen, helium, argon, oxygen, or laboratory atmosphere, and are likely to be associated with thin film porosity.
- OSTI ID:
- 20787929
- Journal Information:
- Journal of Applied Physics, Vol. 99, Issue 5; Other Information: DOI: 10.1063/1.2179969; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
High critical currents in strained epitaxial YBa sub 2 Cu sub 3 O sub 7 minus. delta. on Si
ARMY GAS-COOLED REACTOR SYSTEMS PROGRAM SUMMARY REPORT ON MATERIALS FOR THE GCRE-II
Related Subjects
ANNEALING
ARGON
ATMOSPHERIC PRESSURE
CHEMICAL VAPOR DEPOSITION
CRYOGENICS
HELIUM
NITROGEN
OXIDATION
OXYGEN
PLASMA
SILICON
SILICON NITRIDES
STRESSES
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TENSILE PROPERTIES
THERMAL CYCLING
THERMAL EXPANSION
THIN FILMS
YOUNG MODULUS