NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Measured cross sections and ion energies for a CHF3 discharge.
Published
Author(s)
B. Peko, R. Champion, MVVS. Rao, James K. Olthoff
Abstract
Trifluoromenthane (CHF3) is used in semiconductor plasma processing chambers to achieve high etch selectivity of an oxide layer over a silicon substrate. Such surface etching is governed by the ion and molecule fluxes near the surface, the concentrations of which are dependent upon species interactions in and their transport through the plasma. In order to assist in the interpretation of ion flux measurements and to provide fundamental data required for plasma modeling, we report the first total cross sections for significant ion-molecular reactions occurring in CHF3 discharges. The reactions studied include collision induced dissociation for CF3+ on CHF3, dissociative charge transfer for CF3+, and F+ on CHF3 and electron detachment from F on CHF3. Collision energies range from a few to a few hundred electron volts. In addition, ion-flux energy distributions and relative ion intensities have been measured and are presented for d. c. townsend discharges with E/N values ranging from 5 x 10-18 to 25 x 10 -18 V m2 [5 to 25 kTd]. The Townsend discharge results are qualitatively interpreted using the cross section measurements.
Peko, B.
, Champion, R.
, Rao, M.
and Olthoff, J.
(2002),
Measured cross sections and ion energies for a CHF<sub></sub>3 discharge., Journal of Applied Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=9195
(Accessed October 10, 2025)