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T. Frischmuth, M. Schneider, I. Bogdanović Radović, Z. Siketić, D. Maurer, Th. Grille, U. Schmid:
"Lowtemperature deposition of a-SiC:H thin films applying a dual plasma source process";
Thin Solid Films, 616 (2016), S. 164 - 171.

The utilization of silicon carbide (SiC) thin films is of great interest whenever a high robustness is requested for
MEMS/NEMS-based devices, which are operated in harsh environments beyond the applicability of standard
silicon technology. Hydrogenated amorphous SiC (a-SiC:H) is especially attractive for these scenarios, as it can
be deposited at temperatures lower than 400 °C while still being beneficial for enhanced device performance.
Furthermore, the thin film properties can be tailored to a great extent during synthesis or via post-deposition
annealing. This study reports on the deposition of a-SiC:H thin films at a substrate temperature of 250 °C applying
a dual plasma process by superimposing a radio frequency (RF) plasma which excites the substrate table to an
inductively-coupled RF plasma. This auxiliary plasma source has a huge impact on the resulting thin film properties
due to the interaction of various opposing processes during film growth. To understand these processes, the
layer composition was determined using time-of-flight elastic recoil detection analyses, Fourier transforminfrared
spectroscopy and by mass effusion measurements up to 1000 °C, thus revealing changes in chemical composition,
but also the power dependent incorporation of gaseous species from the plasma. This, for example, allows
modification of the residual stress ranging fromnearly stress free to highly compressively stressed layers ofmore
than−2 GPa, Young's modulus values ranging from about 168 GPa down to 48 GPa, but also greatly affects the
surface topography which can be adjusted to a very low root mean squared roughness of less than 0.1 nm.

The utilization of silicon carbide (SiC) thin films is of great interest whenever a high robustness is requested for
MEMS/NEMS-based devices, which are operated in harsh environments beyond the applicability of standard
silicon technology. Hydrogenated amorphous SiC (a-SiC:H) is especially attractive for these scenarios, as it can
be deposited at temperatures lower than 400 °C while still being beneficial for enhanced device performance.
Furthermore, the thin film properties can be tailored to a great extent during synthesis or via post-deposition
annealing. This study reports on the deposition of a-SiC:H thin films at a substrate temperature of 250 °C applying
a dual plasma process by superimposing a radio frequency (RF) plasma which excites the substrate table to an
inductively-coupled RF plasma. This auxiliary plasma source has a huge impact on the resulting thin film properties
due to the interaction of various opposing processes during film growth. To understand these processes, the
layer composition was determined using time-of-flight elastic recoil detection analyses, Fourier transforminfrared
spectroscopy and by mass effusion measurements up to 1000 °C, thus revealing changes in chemical composition,
but also the power dependent incorporation of gaseous species from the plasma. This, for example, allows
modification of the residual stress ranging fromnearly stress free to highly compressively stressed layers ofmore
than−2 GPa, Young's modulus values ranging from about 168 GPa down to 48 GPa, but also greatly affects the
surface topography which can be adjusted to a very low root mean squared roughness of less than 0.1 nm.

Hydrogenated amorphous silicon carbide Inductively coupled plasma enhanced chemical vapor deposition Microelectromechanical systems Young's modulus Hardness Mass effusion Surface roughness Fourier transform infrared spectroscopy

http://dx.doi.org/10.1016/j.tsf.2016.07.030