{"title":"Structural, thermal and electrical properties of plasma deposited a-C:F films","authors":"Zhenyu Wu, Yintang Yang, JiaYou Wang","doi":"10.1109/POLYTR.2005.1596521","DOIUrl":null,"url":null,"abstract":"Flurinated amorphous carbon (a-C:F) films were deposited at room temperature using C<inf>4</inf>F<inf>8</inf>and CH<inf>4</inf>as precursor gases by electron cyclotron resonance chemical vapour deposition (ECR-CVD). Chemical compositions and bond structures were investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). CF=C (1680cm<sup>-1</sup>), as well as CF<inf>2</inf>=CF (1780cm<sup>-1</sup>) that acted as termination groups of the cross-linking film structure were identified in the deposited a-C:F films. C 1s peaks were assigned to CF<inf>3</inf>(295eV), CF<inf>2</inf>(293eV), CF(291eV), C-O(289eV), C-CF<inf>x</inf>(x=1∼3) (287eV) and C-C termination bond(285eV), respectively. The CF<inf>3</inf>and C-C termination bonds were thermally liable and could induce reduction of film thickness after heat treatment through out-gassing effect. The thermal stability of a-C:F films improved with increasing cross-linking C-CF<inf>x</inf>bonds and decreasing CF<inf>3</inf>and C-C termination bonds. The dissipation factor of the as-deposited metal-insulator-semiconductor capacitor (MIS-C) was approximately 0.07 at 1MHz. The dielectric constant of a-C:F films increased after heat treatment due to reduced electronic polarization and enhanced film density. The interface trap density decreased from (5∼9) ×10<sup>11</sup>eV<sup>-1</sup>cm<sup>-2</sup>to (4∼6) ×10<sup>11</sup>eV<sup>-1</sup>cm<sup>-2</sup>after 300°C annealing in a nitrogen environment. The current-voltage characteristics for a-C:F films was explained using ohmic conduction at low fields and Poole-Frankel(PF) conduction mechanism at high fields. The trap energy of the traps at band tails formed by the delocalized π electrons decreased after annealing, which led to increase of leakage current due to field-enhanced thermal excitation of trapped electrons into the conduction band.","PeriodicalId":436133,"journal":{"name":"Polytronic 2005 - 5th International Conference on Polymers and Adhesives in Microelectronics and Photonics","volume":"38 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2005-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Polytronic 2005 - 5th International Conference on Polymers and Adhesives in Microelectronics and Photonics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/POLYTR.2005.1596521","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Flurinated amorphous carbon (a-C:F) films were deposited at room temperature using C4F8and CH4as precursor gases by electron cyclotron resonance chemical vapour deposition (ECR-CVD). Chemical compositions and bond structures were investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). CF=C (1680cm-1), as well as CF2=CF (1780cm-1) that acted as termination groups of the cross-linking film structure were identified in the deposited a-C:F films. C 1s peaks were assigned to CF3(295eV), CF2(293eV), CF(291eV), C-O(289eV), C-CFx(x=1∼3) (287eV) and C-C termination bond(285eV), respectively. The CF3and C-C termination bonds were thermally liable and could induce reduction of film thickness after heat treatment through out-gassing effect. The thermal stability of a-C:F films improved with increasing cross-linking C-CFxbonds and decreasing CF3and C-C termination bonds. The dissipation factor of the as-deposited metal-insulator-semiconductor capacitor (MIS-C) was approximately 0.07 at 1MHz. The dielectric constant of a-C:F films increased after heat treatment due to reduced electronic polarization and enhanced film density. The interface trap density decreased from (5∼9) ×1011eV-1cm-2to (4∼6) ×1011eV-1cm-2after 300°C annealing in a nitrogen environment. The current-voltage characteristics for a-C:F films was explained using ohmic conduction at low fields and Poole-Frankel(PF) conduction mechanism at high fields. The trap energy of the traps at band tails formed by the delocalized π electrons decreased after annealing, which led to increase of leakage current due to field-enhanced thermal excitation of trapped electrons into the conduction band.