A study of blister formation in ALD Al2O3 grown on silicon

This work investigates the formation of blisters during annealing an Al₂O₃ film grown by atomic layer deposition (ALD) on Si. This blistering phenomenon is shown to occur under an external load in the presence of a tensile residual stress: the total membrane stress is a super-imposition of the residual stress of the pre-stressed film and a concomitant stress due to change of blister profile. In the case of this Si/Al₂O₃ system, the film is indeed pre-stressed and the hydrostatic pressure is caused by (i) the effusion of H₂ and H₂O and (ii) Al₂O₃ being a diffusion barrier.