A stacked capacitor with (Ba/sub x/Sr/sub 1-x/)TiO/sub 3/ for 256M DRAM

Abstract

A high-dielectric-constant material was applied to a practical stacked DRAM capacitor. A large unit area capacitance (40 fF/ mu m/sup 2/) and a low leakage current (<10/sup -7/ A/cm/sup 2/) have been realized by the combination of a thin (Ba/sub x/Sr/sub 1-x/)TiO/sub 3/ film having an equivalent SiO/sub 2/ thickness of 8 AA and a Pt/Ta capacitor electrode. TDDB (time-dependent dielectric breakdown) measurements have indicated good reliability of this novel capacitor cell. These characteristics show that this storage capacitor is quite promising for 256M DRAM cells.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>