Temperature dependence of the mechanical properties of tetrahedrally coordinated amorphous carbon thin films

摘要

The complete elastic properties of tetrahedrally coordinated amorphous carbon (ta-C) thin films have been measured in the temperature range of 300-873 K. Flexural and torsional mechanical oscillators were fabricated from ta-C, and using the resonant frequency of the oscillators as a function of temperature, we calculated the temperature-dependent Young's and shear moduli (658 ± 24 and 271 ± 6.6 GPa, at 300 K, respectively). From these values, we calculated the bulk modulus, Poisson's ratio, and the elastic stiffness and compliance constants as a function of temperature. In addition, the temperature dependence of the coefficient of thermal expansion of ta-C was determined using a wafer curvature technique.