The diffusion-induced bending of both single-layer and bilayer beam structure was analyzed by using linear elastic beam theory and the Moutier theorem. A closed form solution of the radius of curvature due to diffusion was obtained. For the single-layer beam structure, the radius of curvature was inversely proportional to the bending moment created by non-uniform concentration distribution. For the bilayer beam structure, the curvature was a linear function of the mismatch strain between the 2 layers and the bending moment introduced by diffusion. The mismatch strain depended upon the concentration and the partial molar volume of the diffusing component in both layers. Application to micro-electromechanical systems H sensors with a layer of Pd was shown.

Diffusion-Induced Beam Bending in Hydrogen Sensors. F.Yang, J.C.M.Li: Journal of Applied Physics, 2003, 93[11], 9304-9