Improvement in the Cumulative Failure Distribution of High-k Dielectric Subjected to Nanoscale Stress by D₂ Post-Deposition Annealing

By taking advantage of the small contact area of the conductive atomic force microscopy (CAFM) tip with the sample surface, and the powerful measurement capability of the semiconductor parameter analyzer, a nanoscale stress was applied to the atomic-layer-deposited (ALD) HfO₂ high-k dielectrics prepared with N₂, D₂, and no post-deposition anneal (PDA), respectively. The statistical breakdown behavior of ALD HfO₂ under nanoscale stresses was determined and is presented in this paper. It is evident that the cumulative failure distribution of breakdown voltage of high-k dielectrics under nanoscale CVS basically follows the Weibull statistics. We also found that the ALD HfO₂ prepared with D₂ PDA showed an obvious improvement in cumulative failure distribution when compared with those prepared with N₂ PDA and no PDA. The result indicates that D₂ PDA can substantially suppress the generation of defects during the application of nanoscale stress and improve the reliability of high-k dielectrics.