Dresden 2006 – wissenschaftliches Programm
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DS: Dünne Schichten
DS 7: Mechanical properties of thin films
DS 7.7: Vortrag
Montag, 27. März 2006, 17:30–17:45, GER 38
Residual Stress Control in Nanocrystalline Diamond Films — •Nicolas Wöhrl and Volker Buck — Thin Film Technology Group, Dept. of Physics, University of Duisburg-Essen, Universitätsstr. 3-5, 45141 Essen, Germany
Nanocrystalline diamond films were deposited with a microwave CVD plasma source. The nanocrystalline films shown here were deposited in a pressure range between 200 and 300 mbar from an Ar/H2/CH4 plasma. The films were characterized by two wavelength scanning micro Raman spectroscopy, FTIR and SEM measurements.
Residual stress is a critical parameter in thin film deposition and crucial for technical applications of nanocrystalline diamond films because the adhesion of the films on the substrate is affected by the intrinsic stress. High residual stress can lead to cracking or even to delamination of the film from the substrate. An ex-situ optical device (SSIOD ’Surface Stress Induced Optical Deflection’) was used to measure the curvature of silicon substrates coated with nanocrystalline diamond films. With respect to Stoney’s equation one can calculate the residual stress from the curvature of the substrate. Taking the different thermal expansion coefficients of the diamond and the silicon substrate into account the intrinsic stress was determined from the stress measurements. It is shown that the intrinsic stress in the substrate can be varied in a wide range just by controlling the deposition parameters. A possible explanation for the origin of the intrinsic stress is given based on the data taken from Raman Spectroscopy and FTIR Spectroscopy.