TY - THES

T1 - Sputter deposition of amorphous carbon thin films in argon, neon and helium atmospheres

AU - Oberroither, Christoph

N1 - embargoed until 24-05-2022

PY - 2017

Y1 - 2017

N2 - Amorphous carbon films can be deposited by sputtering of solid carbon source materials. The resulting coatings possess a wide range of properties, making them useful for numerous applications. In this thesis, the influence of the deposition gas, the substrate bias and the power density on the deposition process and properties of amorphous carbon films during unbalanced magnetron sputtering of a graphite target was investigated. Carbon films with thicknesses between 1.3 and 2.5 µm were deposited in argon, neon and helium atmospheres, at power densities between 4.4 and 28 W/cm2. The substrate temperature was found to rise with increasing power density, bias voltage and thermal conductivity of the deposition gas. The microstructure of the films was characterized using both X-ray diffraction and Raman spectroscopy, which revealed that the coatings mainly consisted of nano-crystalline graphite with predominant sp2 bonding. The graphitic component increases with rising substrate temperature and power density. With increasing graphitization, the electrical resistivity, elastic modulus and hardness decreased. Films deposited at high bias voltages possess a high impurity content, which leads to elevated residual stress values and consequently high hardness. The residual stresses ranged from -300 to -2900 MPa and hardness values of 9.5 to 33 GPa were obtained. In conclusion, it was found that the substrate temperature and the impurity content are the most influential factors having a major effect on the microstructure of the amorphous carbon films, which leads to changes in their mechanical and electrical properties.

AB - Amorphous carbon films can be deposited by sputtering of solid carbon source materials. The resulting coatings possess a wide range of properties, making them useful for numerous applications. In this thesis, the influence of the deposition gas, the substrate bias and the power density on the deposition process and properties of amorphous carbon films during unbalanced magnetron sputtering of a graphite target was investigated. Carbon films with thicknesses between 1.3 and 2.5 µm were deposited in argon, neon and helium atmospheres, at power densities between 4.4 and 28 W/cm2. The substrate temperature was found to rise with increasing power density, bias voltage and thermal conductivity of the deposition gas. The microstructure of the films was characterized using both X-ray diffraction and Raman spectroscopy, which revealed that the coatings mainly consisted of nano-crystalline graphite with predominant sp2 bonding. The graphitic component increases with rising substrate temperature and power density. With increasing graphitization, the electrical resistivity, elastic modulus and hardness decreased. Films deposited at high bias voltages possess a high impurity content, which leads to elevated residual stress values and consequently high hardness. The residual stresses ranged from -300 to -2900 MPa and hardness values of 9.5 to 33 GPa were obtained. In conclusion, it was found that the substrate temperature and the impurity content are the most influential factors having a major effect on the microstructure of the amorphous carbon films, which leads to changes in their mechanical and electrical properties.

KW - amorphous carbon coating

KW - magnetron sputtering

KW - substrate temperature

KW - Raman spectroscopy

KW - mechanical properties

KW - amorphe Kohlenstoffschichten

KW - Magnetronsputtern

KW - Substrat Temperatur

KW - Raman Spektroskopie

KW - mechanische Eigenschaften

M3 - Diploma Thesis

ER -