The stress in film can be measured by many methods:
1. XRD if the film is crystalline or pollycrystalline
2. Beam deflection technique by depositing the film on flexible substrate: valid for amorphous and polycrystalline film
3. Curvature method by optical technique
I hope this will be useful for you
if you do not give further info, it is hard to answer! You can use several methods to determine the stress in a thin film. Stoney formula is quick and dirt. X-ray diffraction is non destructive and can usually give a rather good estimate. Ellipsometry is also widely employed
Perhaps my paper and more specifically the second half of it, may have some answers to your question - http://www.sciencedirect.com/science/article/pii/S0924424711003256. If you can't download it from sciencedirect.com, I have a near-final version of the paper at my researchgate page.
The stress in film can be measured by many methods:
1. XRD if the film is crystalline or pollycrystalline
2. Beam deflection technique by depositing the film on flexible substrate: valid for amorphous and polycrystalline film
3. Curvature method by optical technique
I hope this will be useful for you
The Stoney technique is OK for both crystal and amorphous material because based on the curvature of the sample. But this technique is not very efficient for a thin film deposited on a rather hard substrate.
If your thin film is crystalline you can use a very efficient technique based on the X ray diffraction called sin square psi method. You can detect a three dimensional stress field in a film as thin as 500 Ang. For details See the article:
B. Lacroix et al in Phys Rew B, 014104 july 2011
X-ray method based on the broadening of the diffraction peaks was applied by us for determination of the coherent scattering domain (CSD) size L and microdeformation level E in CdTe films. Cauchy and Gauss approximations were used to separate diffraction broadening due to the physical effects and tool broadening. Hall approximation was also applied in order to separate the contributions in physical broadening from the dispersive structure of the polycrystalline films and microdeformation. Besides, the level of microdeformations and size of CSD were found directly from the three-fold convolution which describes X-ray broadening. Estimation of mean density of dislocations as well as a total concentration of dislocations were carried out using "E" and "L" values These results are presented in our paper (J. Cryst. Growth, V. 312, 1726 (2010)), which are attached.
Some possible methods for measuring stress in thin films can be found in the following articles:
1. Influence of template type and buffer strain on structural properties of GaN multilayer quantum wells grown by PAMBE. X-Ray study.
V.P. Kladko, A.V. Kuchuk, N.V. Safryuk, V.F. Machulin, P.M. Lytvyn, V.G. Raicheva, A.E. Belyaev, Yu.I. Mazur, E.A. DeCuir Jr, M.E. Ware, and G.J. Salamo // Journal of Physics D: Applied Physics, 2011. V.44. No2, P.025403(8)
2. Substrate effects on the strain relaxation in GaN/AlN short-period superlattices
V.P. Kladko, A.V. Kuchuk, P.M. Lytvyn, O.M. Yefanov, N.V. Safriuk, A.E. Belyaev, Yu.I. Mazur, E.A. DeCuir Jr, M.E. Ware, and G.J. Salamo // Nanoscale Research Letters 2012, 7: 289. (doi:10.1186/1556-276X-7-289).
3. X-ray diffraction analysis and scanning micro-Raman spectroscopy of structural irregularities and strains deep inside the multilayered InGaN/GaN heterostructure.
V.V. Strelchuk, V.P. Kladko, E.A. Avramenko, O.F. Kolomys, N.V. Safryuk, R.V. Konakova, B.S. Yavich, M.Ya. Valakh, V.F. Machulin, and A.E. Belyaev // Semiconductors, 2010, Volume 44, No9, P.1199-1210. DOI: 10.1134/S1063782610090174
On the basis of curvature of thin layer on the thick substrate, for calculation of the stress in thin layers you can use modified Stoney formulas.
For example: the first is the procedure by Vilms-Kerps and Olsen models [1,2];
the second is the procedure given by Klein and Townsend [3,4].
[1] J. Vilms, D. Kerps, „Simple stress formula for multilayered thin films on a thick substrate”, J. Appl. Phys. 53, pp. 1536 - 1537, 1982.
[2] G.H. Olsen, M. Ettenberg, “Calculated stresses in multilayered heteroepitaxial structures”, J. Appl. Phys. 48, pp. 2543 - 2547, 1977.
[3] C.A. Klein, “How accurate are Stoney’s equation and recent modifications”, J. Appl. Phys. 88, pp. 5487 - 5489, 2000.
[4] P.H. Townsend, D.M. Barnett, T.A. Brunner, “Elastic relationships in layered composite media with approximation for the case of thin films on a thick substrate”, J. Appl. Phys. 62, pp. 4438 - 4444, 1987.
It is worth to emhasize that these formulas are proper only for elastically strained layers.
Dear Kotresh,
If the film is poly crystalline or single crystalline in nature then stress in film can change the lattice parameter which is correlated with inter planner spacing.
As you know from Bragg's diffraction equation: d is related to 2 theta. So when you measure intensity vs 2 theta for thin film material then there may be some shift in 2 theta w.r.t. to stress free standard data.
Measure this difference and calculate the d and lattice parameters. XRD can tell you only the effect of stress in film but not the actual value of stress
I hope this may be useful to you
-M
Characterization of optical thin films
H. K. Pulker
29 April 1982Microstructure Of Optical Thin Films
H. A. Macleod;
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