Ferroelectric performance of fully integrated (Bi,La){sub}4Ti{sub}3O{sub}12 capacitor for ferroelectric memory

摘要

We have investigated the ferroelectric performance of Pt/(Bi,La){sub}4Ti{sub}3O{sub}12 (BLT)/Pt capacitor for ferroelectric memory application. The BLT films were deposited using a spin-on process with metalorganic decomposition (MOD) solution. Bi/La content in the solution composition, bake process, and crystallization anneal process were optimized to obtain a good ferroelectric performance. 90 nm-thick BLT (Bi/La 3.37/0.86) films that were crystallized by a modified bake process carried out in more oxidizing ambient than air and an anneal process performed at less than 650℃ in O{sub}2 ambient showed a remnant polarization of 14 μC/cm{sup}2, a coercive voltage of 1.0 V, and a leakage current density of 1×10{sup}(-5) A/cm{sup}2 after SiO{sub}2/Si{sub}3N{sub}4 passivation. These results indicate that BLT films are successfully applicable to the stacked capacitor (capacitor on plug structure) for high density FeRAM.