Film stress measurements for high temperature micromechanical and microelectronical applications based on SiC

Quantitative Evaluation of Strain in Epitaxial 2H-AlN Layers

“…Therefore, the Raman measurements correlates well with the FTIR investigations. A similar nonlinear behaviour of the TO phonon vibration frequencies was found in the case of 3C-SiC layers deposited on silicon substrate grown by chemical vapour deposition[20][21].SummaryThe overall stress in 2H-AlN/3C-SiC(111)/Si (111) heteroepitaxial layer is caused by the mismatch stress and thermo-elastic stress. The increasing Ge concentration at the interface confines the stress in the near interface region and reduces the tensile stress in the upper part of the layer.…”

Measuring coating internal stresses by the curvature method applied to a beveled sample

“…The leading techniques to measure internal stresses probably are the curvature method [4][5][6][7][8][9][10][11][12][13][14], Raman spectroscopy [4,5,8,15] and, in various forms, X-ray diffraction [3,[7][8][9]15,16]. These methods make possible in situ measurements, which allow in particular the evolution of the coating stress to be controlled through the deposition process [5,6].…”

“…These methods make possible in situ measurements, which allow in particular the evolution of the coating stress to be controlled through the deposition process [5,6]. Other techniques however are suitable, such as mechanical spectroscopy (vibrating-reed technique) [15] or neutron diffraction (fairly similar to X-rays from the point of view of the principle) [7,16], even though these latter techniques are not commonly used in the case of films.…”

“…Sometimes, two [4,5,13] or three [7,8] different methods are used jointly, presumably because all the available experimental data on internal stress are not always consistent [8,9]. Indeed, when the methods involve the relative atomic positions and not the stress directly, some discrepancies may arise in the gained stress values.…”

“…The curvature method has been used for a long time through the simple theoretical approach by Stoney [18], the substrate then consisting of a parallel-faced blade of well controlled thickness [4][5][6][7][8][9][10][11][12]. The method is very sensitive as far as a thin substrate can be used (the curvature varies as the inverse of the substrate thickness squared) but, particularly due to handling problems, it may be very delicate to use long and thin blades.…”