Ramanspektroskopische charakterisierung von ultra-dunnen kohlenstoff-schutz-schi

2019-07-20 09:36:37

The different carbon films Raman

责任者: Gradowski, Marc Von;Schneider, Hans-Hermann;Jacoby, Bernd;Ohr, Ralph;Hilgers, Heinz 单位: 来源出处: Vakuum in Forschung und Praxis,2003,15(3):139-145 摘要: Raman-spectroscopy is a standard tool for structural characterization of ultra-thin ( less than or equal 10 nm) amorphous carbon films which are used as protective overcoats in the magnetic storage industry. It provides powerful information on the bonding structure of the films. The Raman-spectra of amorphous carbons are dominated by the D- and G-bands at around 1350 cm-1 - 1600 cm-1 whose position and intensity are used for interpreting the carbon bonding. Several carbon films have been investigated using green (λ = 514.5 nm) and ultraviolet (λ = 244 nm) laser-light. The dispersion of the G-peak is the most crucial of parameters to describe the internal structure of the films since it distinguishes between graphite- and diamond-like carbon. A high G-peak-dispersion corresponds to a high sp3-fraction. These information are not available by single wavelength investigations due to the so called hysteresis effect causing the Raman-spectra of different samples accidentally to look similar albeit having a different internal structure. The dual-method we are here introducing avoids the hysteresis effect and provides good estimations on the sp3-content and the mass density of different carbon systems. Furthermore, UV-Raman analysis leads to quantification of the nitrogen content of nitrogen-doped carbon layers by using the relative intensity of the 2200 cm-1 band in the UV-spectrum. The great advantage of ramanspectroscopic investigations is its celerity. Acquisition times are seldom higher than 1.5 min. Additionally, Raman-spectroscopy is a nondestructive tool which leaves the investigated samples undamaged for further processing and makes it an attractive method for insitu-analysis in the magnetic storage industry. 关键词: Carbon;Ultrathin films;Protective coatings;Nanostructured materials;Magnetic storage;Bonding;Ultraviolet radiation;Laser beams;Diamond like carbon films;Hysteresis;Raman spectroscopy;Mass density