Metal film deposition by laser breakdown chemical vapor deposition
Dielectric breakdown of gas mixtures can be used to deposit homogeneous thin films by chemical vapor deposition with appropriate control of flow and pressure conditions to suppress gas phase nucleation and particle formation. Using a pulsed CO/sub 2/ laser operating at 10.6 microns where there is no significant resonant absorption in any of the source gases, we have succeeded in depositing homogeneous films from several gas phase precursors by gas phase laser pyrolysis. Nickel and molybdenum from the respective carbonyls and tungsten from the hexafluoride have been examined to date. In each case the gas precursor is buffered to reduce the partial pressure of the reactants and to induce breakdown. The films are spectrally reflective and uniform over a large area. Films have been characterized by Auger electron spectroscopy, x-ray diffraction, pull tests, and resistivity measurements. The highest quality films have resulted from the nickel depositions. Detailed x-ray diffraction analysis of these films yields a very small domain size (approx. 50 A) consistent with rapid quenching from the gas phase reaction zone. This analysis also shows nickel carbide formation consistent with the temperature of the reaction zone and the Auger electron spectroscopy results which show some carbon and oxygen incorporation (8% and 1% respectively). Gas phase transport and condensation of the molybdenum carbonyl results in substantial carbon and oxygen contamination of the molybdenum films requiring heated substrates, a requirement not consistent with the goals of the program to maximize the quench rate of the deposition. Results from tungsten deposition experiments representing a reduction chemistry instead of the decomposition chemistry involved in the carbonyl experiments are also reported.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 5323661
- Report Number(s):
- LA-UR-85-2902; CONF-8509150-1; ON: DE85017554
- Resource Relation:
- Conference: NATO advanced study institute, San Mianiato, Italy, 2 Sep 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHEMICAL VAPOR DEPOSITION
MOLYBDENUM
NICKEL
TUNGSTEN
CARBON DIOXIDE LASERS
LASER-RADIATION HEATING
CHEMICAL COATING
DEPOSITION
ELEMENTS
GAS LASERS
HEATING
LASERS
METALS
PLASMA HEATING
SURFACE COATING
TRANSITION ELEMENTS
360101* - Metals & Alloys- Preparation & Fabrication