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  • Print publication year: 2010
  • Online publication date: July 2014

6 - Elastic stress and strain in thin films



Thin films are not used as structural parts in electronic devices to carry mechanical loads. Nevertheless, stress or strain does exist commonly in thin films as a result of constraints imposed by their substrates. A thin film and its substrate generally have different thermal expansion coefficients, so stress is produced during temperature excursion in deposition and annealing. Stress in thin films is known to cause serious yield and reliability problems in microelectronic devices. Ni thin film is known to have a high tensile stress deposited by e-gun or by sputtering at room temperature. In epitaxially grown silicon or a silicon-germanium layer, stress can affect the mobility of the carriers, and stress is introduced in devices for the purpose. In this chapter, we shall discuss the nature of biaxial stress in thin films, and the measurement of biaxial stress in thin films using the wafer-bending method. The chemical potential in a stressed solid that affects atomic diffusion and the time-dependent response of a solid to applied stresses in creep or stress-migration will be covered in Chapter 14.

A piece of solid is under stress when its atoms are displaced from their equilibrium positions by a force [1–6]. The displacement is governed by the interatomic potential.

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[1] R. P., Feynman, R. B., Leighton and M., Sands, The Feynman Lectures on Physics (Vol. II, Ch. 38) (Addison-Wesley, Reading, MA, 1964).
[2] J. P., Hirth and J., Lothe, Theory of Dislocations (McGraw-Hill, New York, 1969).
[3] R. W., Hoffman, “Nanomechanics of thin films: emphasis: tensile properties,” in Physics of Thin Films (Vol. 3, p. 211), eds G., Hass and R. E., Thun (Academic Press, New York, 1964).
[4] H. B., Huntington, “The elastic constants of crystals,” in Solid State Physics, Vol. 7, eds F., Seitz and D., Turnbull (Academic Press, New York, 1958).
[5] N. F., Mott and H., Jones, The Theory of the Properties of Metals and Alloys (Dover, New York, 1958).
[6] A. S., Nowick and B. S., Berry, Anelastic Relaxation in Crystalline Solids (Academic Press, New York, 1972).
[7] M., Murakami and A., Segmiiller, in Analytical Techniques for Thin Films, eds K. N., Tu and R., Rosenberg, Vol. 27 in Treatises on Materials Science and Technology (Academic Press, Boston, 1988).
[8] A. J., Schell-Sorokin and R. M., Tromp, “Mechanical stresses in (sub)monolayer epitaxial films,” Phys. Rev. Lett. 64 (1990), 1039.
[9] P., Chaudhari, “Grain growth and stress relief in thin films,” J. of Vac. Sci. Tech. 9 (1972), 520.
[10] W. D., Nix, “Mechanical properties of thin films,” Metallurgical Transaction, A. Physical Metallurgy and Materials Science 20 (1989), 2217-2245.
[11] F., Spaepen, “Interfaces and stress in thin films,” Acta Mat. 48 (2000), 31-42.