Ta/sub 2/O/sub 5/ capacitors' dielectric material for giga-bit DRAMs

Abstract

We fabricated 256-Mbit DRAM cells using a 0.5 /spl mu/m high CROWN capacitor with crystallized Ta/sub 2/O/sub 5/ dielectric film. We confirmed that the crystallized Ta/sub 2/O/sub 5/ (3.3 nm of SiO/sub 2/-equivalent thickness) was very stable in the conventional metallization process. The key issues for manufacturing were to eliminate the hydrocarbon contaminants during high temperature O/sub 2/ annealing. Our preliminary investigation of Ta/sub 2/O/sub 5/ metal-insulator-metal (MIM) capacitors suggested that it is possible to fabricate 1-Gbit DRAM cells using the amorphous Ta/sub 2/O/sub 5/ MIM capacitor with a CROWN structure.