Plasma-enhanced etching of tungsten, tungsten silicide, and molybdenum in chlorine-containing discharges
Thin films of tungsten, tungsten silicide, and molybdenum were etched both within and downstream from Cl{sub 2} discharges. Without a discharge, molecular chlorine did not etch the films. Experimental conditions ranged from 0.1 to 1.0 Torr pressure, 30 to 180{degree}C electrode temperature, 0.2 to 1.0 W/cm{sup 2} power density, and 3 to 200 sccm flow rate. In-discharge etch rates varied from 10 to 90 nm/min for tungsten (W), 10 to 450 nm/min for tungsten silicide (WSi{sub x}), and 1 to 8 nm/min for molybdenum (Mo). Small additions of BCl{sub 3}, during W and WSi{sub x} etching, significantly increased the etch rates and improved the reproducibility. When samples were positioned downstream from a Cl{sub 2} discharge, etching proceeded solely by chemical reaction of the film with chlorine atoms. Downstream and in-plasma tungsten etch rates were approximately equal at 110{degree}C, but the chlorine atom etch rate dropped more rapidly than the in-plasma etch rate as temperature decreased. In contrast, molybdenum etched faster by atoms alone than in the plasma, although atom etching was not observed below 100{degree}C. Reactions of tungsten with a modulated beam of chlorine atoms and molecules were also studied.
- Research Organization:
- California Univ., Berkeley, CA (USA)
- OSTI ID:
- 7145269
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
CHLORINE
ELECTRIC DISCHARGES
ETCHING
MOLYBDENUM
TUNGSTEN
TUNGSTEN SILICIDES
CHEMICAL REACTIONS
THIN FILMS
ELEMENTS
FILMS
HALOGENS
METALS
NONMETALS
REFRACTORY METAL COMPOUNDS
SILICIDES
SILICON COMPOUNDS
SURFACE FINISHING
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUNGSTEN COMPOUNDS
640410* - Fluid Physics- General Fluid Dynamics
360101 - Metals & Alloys- Preparation & Fabrication
360201 - Ceramics
Cermets
& Refractories- Preparation & Fabrication