A multi-layer diffusion medium substrate having improved mechanical properties is disclosed. The diffusion medium substrate includes at least one stiff layer and at least one compressible layer. The at least one stiff layer has a greater stiffness in the x-y direction as compared to the at least one compressible layer. The at least one compressible layer has a greater compressibility in the z direction. A method of fabricating a multi-layer diffusion medium substrate is also disclosed.