This article is on the experimental estimation of the fracture toughness of thin diamond film deposited by the microwave plasma chemical vapor deposition method on a quartz glass substrate. Because of their differences in the coefficient of thermal expansion, diamond films on a quartz glass substrate suffer tensile stress at room temperature and show various kinds of spontaneous fracture behavior, reflecting the mechanical properties of the films. On the basis of detailed observation of cracking patterns and also measuring the residual stress with the aid of Raman spectroscopy, the fracture toughness of the film having thickness of around 1 μm has been estimated here satisfactorily without the help of any difficult microscopic experiment. The fracture toughness of the film of thickness 0.35 μm is found to be around half of that obtained with much thicker films.
ASJC Scopus subject areas
- Physics and Astronomy(all)