Reactive ion etching of sputtered silicon carbide and tungsten thin films for device applications

Miscellaneous · Fri Jan 01 00:00:00 EST 1988

OSTI ID:6506475

Pan, W S

For high temperature processing and device applications refractory materials, silicon carbide (SiC) and tungsten (W), are considered or evaluated as the basic semiconductor and metallization materials for integrated circuits. In order to pattern fine lines in SiC and W thin films, a selective and anisotropic etching technique is needed. First, materials properties, such as crystallinity, conductivity, refractive index, optical bandgap, etc., of sputtered silicon carbide (SiC) and tungsten (W) thin films have been investigated in conjunction with the rapid thermal annealing (RTA) technique. The RTA temperature dependence of the optical bandgap of SiC thin films has been obtained. High crystallinity W thin of low resistivity films were obtained using by RTA. Reactive ion etching (RIE) of SiC thin films in a variety of fluorinated gas plasmas, such as SF{sub 6}, CBrF{sub 3} and CHF{sub 3} mixed with oxygen has been investigated in depth. The emission spectra and induced DC bias of the RF plasma were monitored to explore the etching mechanisms. A SiC:Si etch ratio higher than unity was obtained for the first time by using CBrF{sub 3}/75%O{sub 2} and CHF{sub 3}/90%O{sub 2} at 200W, 20 sccm, 20mTorr plasma conditions. The best anisotropic profile was observed by using CHF{sub 3} gas in the RIE mode. A typical DC bias, -300V, is concluded from etching experiments to determine the dependence of SiC etch rate and physical reaction under RIE mode. RIE of tungsten (W) thin film was investigated by using the different fluorinated gas plasmas, such as CF{sub 4}, SF{sub 6}, CBrF{sub 3} and CHF{sub 3} mixed with oxygen. We have achieved our goal of selective patterning of tungsten films over SiC, Si, SiO{sub 2}, which required in order to use W in SiC device applications. A very good W:Si and W:SiO{sub 2} selective ratio, 4:1 and 4.8:1, were observed by using CHF{sub 3}/70%O{sub 2} gases under different Plasma conditions.

• Research Organization: Rensselaer Polytechnic Inst., Troy, NY (USA)
• OSTI ID: 6506475
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
36 MATERIALS SCIENCE
SEMICONDUCTOR DEVICES
DESIGN
FABRICATION
BENCH-SCALE EXPERIMENTS
COMPUTER ARCHITECTURE
ETCHING
INFORMATION SYSTEMS
PHYSICAL PROPERTIES
REACTIVITY
SILICON CARBIDES
SPUTTERING
SURFACE PROPERTIES
THIN FILMS
TUNGSTEN
CARBIDES
CARBON COMPOUNDS
ELEMENTS
FILMS
METALS
SILICON COMPOUNDS
SURFACE FINISHING
TRANSITION ELEMENTS
990200* - Mathematics & Computers
990300 - Information Handling
360204 - Ceramics
Cermets
& Refractories- Physical Properties