Kinetic study of the plasma-etching process. I. A model for the etching of Si and SiO/sub 2/ in C/sub n/F/sub m//H/sub 2/ and C/sub n/F/sub m//O/sub 2/ plasmas

Journal Article · Thu Apr 01 04:00:00 EST 1982 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.331074· OSTI ID:5659043

Kushner, M J

A kinetic model of the plasma-etching process has been developed to describe the etching of Si and SiO/sub 2/ in C/sub n/F/sub m//O/sub 2/ and C/sub n/F/sub m//H/sub 2/ plasmas (C/sub n/F/sub m/ equivalentCF/sub 4/, C/sub 2/F/sub 6/). The model has obtained good agreement with experiment for demonstrating the selective etching of SiO/sub 2/ in C/sub n/F/sub m//H/sub 2/ plasmas, and the enhancement of the etch rate of Si in C/sub n/F/sub m//O/sub 2/ plasmas. Good agreement is also obtained with mass spectroscopic measurements of neutral species from a CF/sub 4//H/sub 2/ plasma. Results from the model indicate that the adsorption of atomic hydrogen on silicon surfaces from C/sub n/F/sub m//H/sub 2/ plasmas, which then reacts with adsorbed fluorine, can significantly effect the selectivity of etching SiO/sub 2/ with respect to Si. Similarly, the adsorption of atomic oxygen, which then reacts with adsorbed carbon thereby cleansing the surface, may be responsible for the large etch rates of Si seen in C/sub n/F/sub m//O/sub 2/ plasmas. The selectivity of etching SiO/sub 2/ in C/sub n/F/sub m//H/sub 2/ plasmas has been found to be a sensitive function of the C/F ratio of the carbon-bearing molecules which desorb from the surface, and a C/F ratio of 0.5 shows best agreement with experiment. Results from the model favor ion drift as a dominant mechanism by which radicals are transported to the surface.

• Research Organization: Sandia National Laboratories, Division 4216, Albuquerque, New Mexico 87185
• OSTI ID: 5659043
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 53:4; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360604* -- Materials-- Corrosion
Erosion
& Degradation
ADSORPTION
CARBON COMPOUNDS
CARBON FLUORIDES
CHALCOGENIDES
COMPARATIVE EVALUATIONS
DATA
ELEMENTS
ETCHING
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN
INFORMATION
KINETICS
MASS SPECTROSCOPY
MATHEMATICAL MODELS
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PLASMA
SEMIMETALS
SILICON
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
SPECTROSCOPY
SURFACE FINISHING
SURFACES
THEORETICAL DATA