Constraint annealing of HfO₂ films on silicon substrate: Suppression of Si outward emission

Flexural tensile and compressive constraints were applied mechanically to the 7.5 nm thick HfO₂ films on Si substrates to investigate the influences of stress on the Si outward emission behavior in Si/HfO₂ during annealing. The constraint stress inhibited further growth of the interfacial layer (IL) between HfO₂ and Si, suppressing the IL-growth-induced Si outward emission. This fact was associated with atomic rearrangement that was induced during constrained annealing, resulting in the formation of a robust HfO₂ layer with low oxygen vacancy. Such an HfO₂ layer effectively suppressed the inward diffusion of oxygen, the IL growth and the Si out-diffusion.