  In this work, optical profilometry and finite-element simulations are applied
on buckled micro-machined membranes for the stress analysis of
ion-beam-sputtered $\mathrm{Ta_{2}O_{5}}$ and $\mathrm{SiO_{2}}$ thin films.
Layers with different thicknesses are grown on silicon substrates, then several
membranes with different geometries are manufactured with standard micro-system
technologies; due to a high level of the films' compressive stress, buckled
membranes are obtained. Thermally-grown silica membranes are also produced, for
comparison. The residual stress values are determined by comparing the measured
and simulated deflections of the membranes. The average stress state of the
$\mathrm{Ta_{2}O_{5}}$ thin films is found to be $-209$ MPa. The
$\mathrm{SiO_{2}}$ thin films are in a higher compressive stress state whose
average value is $-576$ MPa. The average stress in thermal $\mathrm{SiO_{2}}$
thin layers grown at 1130 $^{\circ}$C is found equal to $-321$ MPa, in good
agreement with the literature.

Applied Physics;Soft Condensed Matter