Y. Konishi et al., Measurement of hydrogen content in ultrathin diamond-like carbon films using low-energy elastic recoil detection analysis, DIAM RELAT, 9(3-6), 2000, pp. 746-751
We performed direct measurement of hydrogen content in diamond-like carbon
(DLC thin films using elastic recoil detection analysis (ERDA) of hydrogen
atoms forward-scattered by a 2 keV beam of helium ions. DLC films were prep
ared in an electron cyclotron resonance (ECR) microwave plasma chemical vap
or deposition (CVD) system. Use of a low-energy beam in conjunction with a
small incidence angle allowed measurements of hydrogen content in the surfa
ce region of films of various thickness (2.4, 5 and 100 nm). Analysis of re
sultant spectra indicates that a higher negative substrate bias voltage pro
duces lower hydrogen content; these findings are consistent with those obta
ined on thick DLC films using high-energy (2-3 MeV) ERDA. Accordingly, this
confirms the suitability of using the low-energy ERDA system described to
measure hydrogen content in ultrathin (< 5 nm) DLC films. The relationship
between film hardness and hydrogen content in such films is also discussed,
as is the effect of film thickness on hydrogen content. (C) 2000 Elsevier
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