Startsida
Hjälp
Sök i LIBRIS databas

     

 

Sökning: onr:21622459 > CVD Chemistry of Or...

  • Imam, Mewlude,1983- (författare)

CVD Chemistry of Organoborons for Boron-Carbon Thin Film Depositions / Mewlude Imam

  • E-bokAvhandlingEngelska2017

Förlag, utgivningsår, omfång ...

  • Publicerad:Linköping :Publicerad:Department of Physics, Chemistry and Biology, Linköping University,Publicerad:2017
  • 1 onlineresurs (142 sidor)illustrationer
  • 47 sidordiagram, formler
  • txtrdacontent
  • crdamedia
  • crrdacarrier

Nummerbeteckningar

  • LIBRIS-ID:21622459
  • Ogiltigt nummer / annan version:9789176855270
  • http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-141548uri
  • urn:nbn:se:liu:diva-141548urn
  • 10.3384/diss.diva-141548doi

Kompletterande språkuppgifter

  • Språk:engelska

Ingår i deldatabas

Klassifikation

Serie

  • Linköping Studies in Science and Technology. Dissertations,0345-7524 ;1849

Anmärkningar

  • Härtill 4 uppsatser
  • Teknologie doktorsexamen
  • Doctor of Philosophy (PhD)
  • Teknologie doktorsexamen
  • Diss. (Sammanfattning) Linköping : Linköpings universitet, 2017
  • gratis
  • Boron-carbon thin films enriched with 10B are potential neutron converting layers for 10B-based solid state neutron detectors given the good neutron absorption cross section of 10B atoms in thin films. The common neutron-transparent base material, Al (melting point 660 °C), limits the deposition temperature and the use of chlorinated precursors forming corrosive by-products such as HCl. Therefore, the organoborons triethylboron B(C2H5)3 (TEB) and trimethylboron B(CH3)3 (TMB) are evaluated as precursors for CVD of BxC films. In order to get a complete understanding of the CVD behaviour of these precursors for deposition of boron containing films, both thermal CVD and plasma CVD of BxC films have been demonstrated. A gas phase chemical mechanism at the corresponding thermal CVD conditions was proposed by quantum chemical calculations while chemical mechanism in the plasma was suggested based on plasma composition obtained from Optical emission spectroscopy (OES). The behaviours of TEB and TMB in thermal CVD are investigated by depositing BxC films in both H2 and Ar atmospheres, respectively. Films deposited using TEB within a temperature window of 600 – 1000 °C are X-ray amorphous with 2.5 ≤ x ≤ 4.5. The impurity level of H is less than 1 at. % above 600 °C. Calculations predict that the gas phase reactions are dominated by β-hydride eliminations of C2H4 to yield BH3. In addition, a complementary bimolecular reaction path based on H2 assisted C2H6 elimination to BH3 is also present at lower temperatures in the presence of hydrogen molecules. As for films deposited with TMB, dense, amorphous, boron rich (B/C = 1.5-3) films are obtained at 1000 °C in both H2 and Ar atmosphere.  The quantum chemical calculations suggest that the TMB molecule is mainly decomposed by unimolecular α- elimination of CH4 complemented by H2 assisted elimination of CH4. Plasma CVD of BxC thin films has been studied using both TMB and TEB as single-source precursors in an Ar plasma at temperatures lower than that allowed by thermal CVD. The effect of plasma power, TMB/TEB and Ar gas flow on film composition and morphology are investigated. The highest B/C ratio of 1.9 is found for films deposited at highest plasma power (2400 W) and high TMB flow (7 sccm). The H content in the films stays almost constant at 15±5 at. %. The B-C bonding is dominant in the films while small amounts of C-C and B-O exist, likely due to formation of amorphous carbon and surface oxidation. Film density is determined as 2.16±0.01 g/cm3 and the internal compressive stresses are measured to be less than 400 MPa. OES shows that TMB is decomposed to mainly atomic H, C2, BH, and CH. A plasma chemical model for decomposition of the TMB is constructed using a combination of film and plasma composition. It is suggested that the decomposition of TMB starts with dehydrogenation of the methyl groups followed by breakage of the B-C bonds to form the CH radicals. This bond breaking is at least partly assisted by hydrogen in forming the BH radicals. When films are deposited using TEB flow of 5 and 7 sccm, the B/C ratio is found to be plasma power dependent while the carbon content is almost not affected. The highest B/C ratio of 1.7 is obtained at the highest power applied (2400 W) and attributed to better dissociation of TEB at higher plasma power. The H content in the films is within 14-20 at. %. The density of films is increased to 2.20 g/cm3 with increasing plasma power and attributed to a higher energetic surface bombardment during deposition. The oxygen content in the film is reduced to less than 1 at. % with increasing plasma power due to the densification of  the films preventing surface oxidation upon air exposure. Plasma composition from OES shows that the TEB molecules are also dissociated mainly to BH, CH, C2 and H. A plasma chemical model where the first ethyl group is split off by β-hydrogen elimination to form C2H4, which is further dehydrogenated to C2H2 and  forms C2 and CH is suggested. The BH species is assumed to be formed by the dehydrogenation of remaining ethyl groups and breakage of the remaining B-C bonds to form BH.
  • Med populärvetenskaplig sammanfattning på svenska

Ämnesord och genrebeteckningar

Biuppslag (personer, institutioner, konferenser, titlar ...)

  • Pedersen, Henrik1981- (preses)
  • Birch, Jens1960- (preses)
  • Leskelä, Marrku (opponent)
  • Linköpings universitet.Institutionen för fysik, kemi och biologi (utgivare)
  • Linköpings universitetTekniska fakulteten (utgivare)

Sammanhörande titlar

  • Del av/supplement till:channel record
  • Annan version:Även utgiven trycktCVD Chemistry of Organoborons for Boron-Carbon Thin Film Depositions9789176855270

Seriebiuppslag

  • Linköping Studies in Science and Technology.Dissertations,0345-7524 ;1849

Internetlänk

Länkade data-URI:er (test)

  • 392262 (Imam, Mewlude, 1983- aut)
  • 159972 (Tunnfilmsteknik sao)
  • 274895 (Fysik sao)
  • 264446 (Naturvetenskap hsv)
  • 383647 (Kemi hsv)
  • 264446 (Naturvetenskap hsv)
  • 274895 (Fysik hsv)
  • 317364 (Pedersen, Henrik 1981- ths)
  • 243422 (Linköpings universitet. Institutionen för fysik, kemi och biologi pbl)
Inställningar Hjälp

Titeln finns på 1 bibliotek. 

Bibliotek i östra Sverige (1)

Ange som favorit
Om LIBRIS
Sekretess
Blogg
Hjälp
Fel i posten?
Kontakt
Teknik och format
Sök utifrån
Sökrutor
Plug-ins
Bookmarklet
Anpassa
Textstorlek
Kontrast
Vyer
LIBRIS söktjänster
SwePub
Sondera
Uppsök

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

Copyright © LIBRIS - Nationella bibliotekssystem

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy