Ultra-thin EBL (encapsulated barrier layer) for ferroelectric capacitor

A new EBL (encapsulating barrier layer), Al/sub 2/O/sub 3/, was developed in order to preserve the excellent ferroelectric characteristics of PZT capacitors throughout the integration process of FRAMs. From the fully working double-level metal, one-poly, 1T/1C 64 k PZT FRAM, Al/sub 2/O/sub 3/ films with thickness in the range of 60 /spl Aring/ to 100 /spl Aring/ showed excellent barrier properties against the hydrogen attack, reaction between PZT film and IMD, and out diffusion of the volatile component in the capacitor. Moreover, the excellent insulating properties of ultra-thin Al/sub 2/O/sub 3/ EBL offered the reduction of one photo/etch step during the full integration process, which required for the conventional TiO/sub 2/ one.