Observations of. beta. -tungsten deposited by low pressure chemical vapor deposition

Journal Article · Sun Mar 01 23:00:00 EST 1987 · Appl. Phys. Lett.; (United States)

DOI:https://doi.org/10.1063/1.98156· OSTI ID:6986711

Paine, D C; Bravman, J C; Yang, C Y

Metastable ..beta..-tungsten was identified, using transmission electron microscopy, in arrays of low pressure chemical vapor deposited contacts on patterned silicon wafers. In contrast, only ..cap alpha..-tungsten was found in films deposited onto bare silicon wafers under identical conditions. Thus, we have shown that contact wells etched through oxide can play a role in determining which tungsten phase is deposited by low pressure chemical vapor deposition. This effect was observed for a variety of furnace conditions (T = 300--330 /sup 0/C, H/sub 2//WF/sub 6/ = 150:1--400:1). Transmission electron micrographs and selected area diffraction patterns are presented which illustrate the microstructural differences between the ..cap alpha..- and ..beta..-tungsten phases. Possible sources of oxygen or fluorine, impurities which are believed to stabilize ..beta..-tungsten, are discussed and related to the geometry of the vias cut through oxide on patterned wafers.

• Research Organization: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305
• OSTI ID: 6986711
• Journal Information: Appl. Phys. Lett.; (United States), Journal Name: Appl. Phys. Lett.; (United States) Vol. 50:9; ISSN APPLA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
COATINGS
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DEPOSITION
ELECTRON MICROSCOPY
ELEMENTS
ETCHING
FILMS
METALS
MICROSCOPY
MICROSTRUCTURE
PHASE STUDIES
PHASE TRANSFORMATIONS
SEMIMETALS
SILICON
SURFACE COATING
SURFACE FINISHING
THIN FILMS
TRANSITION ELEMENTS
TRANSMISSION ELECTRON MICROSCOPY
TUNGSTEN
VAPOR DEPOSITED COATINGS