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1 December 1990 Mechanical property measurement of polycrystalline diamond films
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Abstract
The biaxial modulus and residual (post deposition) stress of polycrystalline diamond (PCD) films deposited by microwave plasma CVD is determined using the bulge test technique. This method involves measuring the deflection of a circular membrane under an applied differential pressure. A calibration parameter for the bulge test is determined by evaluating the biaxial modulus of a silicon specimen standard. The film is characterized using X-Ray diffraction. Preliminary results yield a biaxial modulus value of 960 GPa for the PCD film. 1. INTRODUCFION Diamond inherently exhibits several unique physical and optical properties enabling its use in various applicalions. Its large bandgap (5. 45 evi) and covalently bonded aliphatic sp hybridized carbon atoms arranged t. eirahedrally result in an optical transparency in wavelength from 220 to 2500 nm and wavelengths above 6000 nm (beyond mid-infrared). Diamond is extremely hard highly thermally conductive and has both low coefficient of thermal expansion as well as high elastic modulus. This combination of properties results in diamond being extremely resistant to thermal shock as is characterized by the thermal shock resistance figure of merit R: (1v)nc R Ea where v equals the Poisson ratio a is the fracture strength ic is the thermal conductivity E the elastic (Young''s) modulus and a is the coefficient of thermal expansion2. Similarly the damage velocity threshold v1 for brittle materials impacted by water drops has been has been related to the
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Gregory Frank Cardinale and Randal W. Tustison "Mechanical property measurement of polycrystalline diamond films", Proc. SPIE 1325, Diamond Optics III, (1 December 1990); https://doi.org/10.1117/12.22448
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