Development of a Pb(Zr,Ti)O3 capacitor employing an IrO x /Ir bottom electrode for highly reliable ferroelectric random access memories

A highly {111}-oriented metal-organic CVD Pb(Zr,Ti)O-3 (PZT) is successfully developed using IrOx/Ir instead of Ir as the bottom electrode. The {111} PZT orientation strongly depends on the IrOx thickness and the O-2 content of the atmosphere (PO2) during IrOx deposition. During PZT deposition, the Ir surface easily oxidizes and becomes rough, resulting in poor {111} PZT orientation. IrOx prevents Ir surface oxidation and transforms the Ir metal via O-2 reduction after the PZT deposition completion. Highly {111}-oriented PZT can be obtained by optimizing the IrOx thickness and PO2 content.