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Acetylene–argon plasmas measured at an rf-biased substrate electrode for diamond-like carbon deposition: II. Ion energy distributions

Biomedical Sciences Research Institute Computer Science Research Institute Environmental Sciences Research Institute Nanotechnology & Advanced Materials Research Institute

Baby, A, Mahony, CMO, Lemoine, P and Maguire, PD (2011) Acetylene–argon plasmas measured at an rf-biased substrate electrode for diamond-like carbon deposition: II. Ion energy distributions. Plasma Sources Science and Technology, 20 (015004). [Journal article]

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DOI: 10.1088/0963-0252/20/1/015004

Abstract

Ion energy distributions (IEDs) have been determined at the radio frequency (rf)-biasedelectrode in an inductively coupled acetylene–argon plasma for various substrate bias voltagesand frequencies under conditions suitable for diamond-like carbon (DLC) and polymer-likefilm deposition. These are compared with those obtained at a capacitively coupled plasmagrounded wall. In the former, for pressures <25mTorr, the IEDs exhibit bimodal structureswith peak separation values that follow the expected voltage and frequency dependences. Athigher pressures, 120mTorr, the bimodal structure is replaced by a single peak. For allconditions the dominant ion is Ar+ or ArH+ despite the set flow ratio of C2H2 : Ar of 2 : 1 andthis can be attributed to the high electron dissociation of the parent molecule. DLC filmsindicate a peak hardness at an ion energy of around 90 eV and a very sharp fall in hardness isnoted beyond this value. This is similar to the observed sp3-bond formation in hydrogen-freetetrahedral amorphous carbon or bias-sputtered films. However, due to the lack ofcarbon-based ions, an alternative mechanism is likely based on argon knock-on implantationof surface adsorbed carbon species. The results have shown that the use of high-frequency biasor bias harmonics may lead to much narrower IEDs.

Item Type:Journal article
Faculties and Schools:Faculty of Computing & Engineering
Faculty of Computing & Engineering > School of Engineering
Research Institutes and Groups:Engineering Research Institute
Engineering Research Institute > Nanotechnology & Integrated BioEngineering Centre (NIBEC)
ID Code:17637
Deposited By:Dr Charles Mahony
Deposited On:29 Mar 2011 11:48
Last Modified:29 Mar 2011 11:48

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