Selective tungsten deposition: Temperature-programmed studies on silicon, silicon dioxide, and tungsten surfaces

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5432113

Hindman, G T

Selective tungsten chemical vapor deposition (CVD) is a technique which has shown considerable promise for the semiconductor manufacturing industry due to tungsten's physical properties and its ability to be deposited in a spatially selective manner. Routine employment of selective tungsten deposition has been impeded by a lack of knowledge about processes by which selectivity is lost. In order to better understand the cause of selectivity loss and the chemistry of selective tungsten CVD, the interactions of WF{sub 6} on SiO{sub 2}, Si, and W surfaces were studied in ultra high vacuum (UHV) using Temperature Programmed Reaction Spectroscopy. These experiments revealed that WF{sub 6} is capable of reacting with a native oxide surface even at low temperatures. Tungsten oxyfluorides or silicon oxyfluorides desorption signals were not observed from either thick thermal or thin native oxide surfaces. On Si(100) multiple overlapping WF{sub 6} desorption peaks were observed. These chemisorption peaks shifted to higher temperatures with increasing exposure, and are believed to be due to the decomposition of a W-Si-F corrosion layer. Hydrogen did not adsorb on silicon surfaces containing appreciable amounts of tungsten. Tungsten and silicon rapidly interdiffused in tungsten films grown in situ by silicon reduction. Silicon on or in these in situ W films was more reactive than clean, tungsten-free silicon. Experiments on polycrystalline tungsten revealed that WF{sub 6} adsorption is partially irreversible.

• Research Organization: Arizona State Univ., Tempe, AZ (United States)
• OSTI ID: 5432113
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360601 -- Other Materials-- Preparation & Manufacture
CHALCOGENIDES
CHEMICAL COATING
CHEMICAL REACTIONS
CHEMICAL VAPOR DEPOSITION
CHEMISORPTION
COATINGS
CRYSTALS
DEPOSITION
ELEMENTS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
MATERIALS
METALS
OXIDES
OXYGEN COMPOUNDS
POLYCRYSTALS
REFRACTORY METAL COMPOUNDS
SEMICONDUCTOR MATERIALS
SEMIMETALS
SEPARATION PROCESSES
SILICON
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
SPECTROSCOPY
SURFACE COATING
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUNGSTEN
TUNGSTEN COMPOUNDS
TUNGSTEN FLUORIDES
VAPOR DEPOSITED COATINGS