Physicochemical properties in tungsten films deposited by radio-frequency magnetron sputtering
The microstructure, reflectivity, resistivity, and oxygen contamination of thin tungsten films (<250 nm) deposited by rf magnetron sputtering on silicon substrates are reported. Three structural stages, depending on the operating conditions, are found to occur during the deposition: (i) In the range of the rf applied power density studied (<6 W cm/sup -2/), an amorphous structure is always observed when the film thickness does not exceed approx.80 nm. The resistivity remains at a fairly high level (approx. =1.3 ..mu cap omega.. m). (ii) Upon further deposition and if the power density is <0.6 W cm/sup -2/, the ..beta..-W phase is detected. (iii) A thermally activated transformation of the ..beta..-W phase into pure ..cap alpha..--W occurs for a critical temperature approx.150 /sup 0/C during depositions carried out at higher powers(greater than or equal to1 W cm/sup -2/). The resulting ..beta..-W or ..cap alpha..-W films consist of small grains (5--20 nm) which present a low dislocation density. Resistivity and reflectivity are mainly related to the oxygen content of the films. When the rf deposition power density is low (less than or equal to0.6 W cm/sup -2/), both high oxygen contamination levels (>10 at. %), large resistivity (>>1 ..mu cap omega.. m), and low reflectivity (<48%) are concurrently observed, whatever the thickness. The oxygen contamination is controlled by the deposition rate and by the substrate temperature. Long-run depositions carried out at high power densities (>2 W cm/sup -2/) exhibit a very low contamination degree (<1 at. %).
- Research Organization:
- Institut Universitaire de Technologie, Universite de Paris Sud (XI), Plateau du Moulon, B. P. 23, 91406 Orsay Cedex, France
- OSTI ID:
- 7202407
- Journal Information:
- J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 6:4; ISSN JVTAD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102 -- Metals & Alloys-- Structure & Phase Studies
360104* -- Metals & Alloys-- Physical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
COATINGS
CONTAMINATION
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DIMENSIONS
DISLOCATIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON TUBES
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
IMPURITIES
LINE DEFECTS
MAGNETRONS
METALS
MICROSTRUCTURE
MICROWAVE EQUIPMENT
MICROWAVE TUBES
OPTICAL PROPERTIES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
REFLECTIVITY
REFRACTIVITY
SEMIMETALS
SILICON
SPUTTERING
SURFACE CONTAMINATION
SURFACE PROPERTIES
THICKNESS
TRANSITION ELEMENTS
TUNGSTEN
VAPOR DEPOSITED COATINGS