Physicochemical properties in tungsten films deposited by radio-frequency magnetron sputtering

Journal Article · Fri Jul 01 00:00:00 EDT 1988 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.575583· OSTI ID:7202407

Collot, P; Agius, B; Estrache, P; Hugon, M C; Froment, M; Bessot, J; Crassin, Y

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), Vol. 6:4
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
TUNGSTEN
ELECTRIC CONDUCTIVITY
IMPURITIES
MICROSTRUCTURE
OPTICAL PROPERTIES
CONTAMINATION
CRYSTAL-PHASE TRANSFORMATIONS
DISLOCATIONS
MAGNETRONS
REFLECTIVITY
REFRACTIVITY
SILICON
SPUTTERING
SURFACE CONTAMINATION
THICKNESS
VAPOR DEPOSITED COATINGS
COATINGS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIMENSIONS
ELECTRICAL PROPERTIES
ELECTRON TUBES
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
LINE DEFECTS
METALS
MICROWAVE EQUIPMENT
MICROWAVE TUBES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SEMIMETALS
SURFACE PROPERTIES
TRANSITION ELEMENTS
360104* - Metals &amp; Alloys- Physical Properties
360102 - Metals &amp; Alloys- Structure &amp; Phase Studies
400201 - Chemical &amp; Physicochemical Properties