Modification of niobium film stress by low-energy ion bombardment during deposition
The effect of ion bombardment on film stress was studied by evaporating Nb thin films in the presence of a controlled ion beam from a Kaufman ion source. Films were deposited at 4 A/s by electron-beam evaporation with ion bombardment over the energy range 100--800 eV, at ion current densities of 0.001 to 1.1 mA/cm/sup 2/. Film stress was measured by an x-ray bending-beam technique on Si substrates. Stress values were found to depend strongly on both ion flux and sample temperature. For films deposited at 400 /sup 0/C, film stress is tensile in the absence of ion bombardment. Increasing argon ion flux causes a change toward compressive stress, in some cases passing through zero. For films deposited at room temperature, film stress is compressive in the absence of ion bombardment, due to incorporation of oxygen. Argon ion bombardment causes a change toward tensile stress, correlating with an improvement in film purity by preferential resputtering of oxygen. With 100 eV argon ions, an ion-to-atom ratio of only 3--10 % is sufficient to cause reversal of the sign of film stress in most cases. Results are interpreted as a combination of cleaning by resputtering and annealing or compacting the film microstructure. In addition, nitrogen ion bombardment is shown to produce superconducting NbN films with a superconducting transition temperature up to 14.5 K.
- Research Organization:
- IBM Thomas J. Watson Research Center, Box 218, Yorktown Heights, New York 10598
- OSTI ID:
- 5457575
- Journal Information:
- J. Vac. Sci. Technol.; (United States), Journal Name: J. Vac. Sci. Technol.; (United States) Vol. 20:3; ISSN JVSTA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360103 -- Metals & Alloys-- Mechanical Properties
360104 -- Metals & Alloys-- Physical Properties
360106* -- Metals & Alloys-- Radiation Effects
640301 -- Atomic
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANNEALING
ARGON
ARGON IONS
BEAMS
CARBON
CHARGED PARTICLES
CHEMICAL ANALYSIS
CLEANING
COLLISIONS
COMPRESSION STRENGTH
CONTAMINATION
CRYSTAL STRUCTURE
DEPOSITION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON BEAMS
ELECTRON MICROPROBE ANALYSIS
ELEMENTS
ENERGY RANGE
EV RANGE
EV RANGE 100-1000
EVAPORATION
FILMS
FLUIDS
GASES
HEAT TREATMENTS
HIGH TEMPERATURE
IMPURITIES
ION BEAMS
ION COLLISIONS
IONS
LEPTON BEAMS
MECHANICAL PROPERTIES
MEDIUM TEMPERATURE
METALS
MICROANALYSIS
MICROSTRUCTURE
NIOBIUM
NITROGEN IONS
NONMETALS
OXYGEN
PARTICLE BEAMS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PHYSICAL RADIATION EFFECTS
QUANTITATIVE CHEMICAL ANALYSIS
RADIATION EFFECTS
RARE GASES
SPUTTERING
SURFACE CLEANING
SURFACE COATING
SURFACE CONTAMINATION
SURFACE FINISHING
TENSILE PROPERTIES
TRANSITION ELEMENTS
VACUUM COATING
VACUUM EVAPORATION