Impurities in dielectrics and hydrogen barriers for SrBi[sub 2]Ta[sub 2]O[sub 9]-based ferroelectric memories

Yang, B.; Oh, S. H.; Chung, C. H.; Noh, K. H.; Kang, Y. M.; Lee, S. S.; Hong, S. K.; Kang, N. S.; Hong, J. H.
September 2001
Applied Physics Letters;9/24/2001, Vol. 79 Issue 13
Academic Journal
We report results of systematic investigation of impurities in dielectrics and hydrogen barriers (Ti and Al[sub 2]O[sub 3] films) during the integration process of SrBi[sub 2]Ta[sub 2]O[sub 9]-based ferroelectric memories. The capacitors integrated with Ti hydrogen barriers are not electrically degraded regardless of the annealing conditions of the subdielectrics. On the contrary, electrical properties of the capacitors using Al[sub 2]O[sub 3] hydrogen barriers significantly depend on the annealing temperatures for subdielectrics. It turned out that interaction of the dielectrics with plasma during sputtering of the Ti films caused fragmentation of the moisture in the dielectrics and absorption of the hydrogen in the Ti films, making annealing irrelevant. However, the alumina films blocked both hydrogen and moisture in the subdielectrics during the passivation process, resulting in dependence on the annealing temperatures. © 2001 American Institute of Physics.


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