Low temperatura cystallization of Strontium Bismuth Tantalate Films

L. RICO; B. J. GÓMEZ; M.G. STACHIOTTI; N. PELLEGRI; J. FEUGEAS; O. DE SANCTIS

Angra do Reis, Rio de Janeiro, Brasil.

Congreso; 12º CLACSA – Latin American Congress of Surfaces Science and its Applications; 2006

Strontium Bismuth Tantalate (SBT) ferroelectric thin films have attracted considerable attention for the development of non-volatile ferroeiectric ramdom access memories (NV-PRAMS) due to its relatively low voltage operation, low leakage current, fast switching and good fatigue resistance with Pt bottom elec- trodes. However, SBT films have a critical problem such as the high processing temperatures ( < 750 OC) that is awkward to be applied to the semiconductor process necessary to the fabrication of FRAhls. The thermal evolution of the SBT films prepared by Chemical Solution Deposition (CSD) showed that firstly an Oxygen deficient fluorite phase is formed at about 550 "C and after, the SBT perovskite phase crystallizes for temperatures higher than 650°C. In order to favor an earlier perovskite crystallization, as-burnt-SBT coated Pt/Ti/Si02/Silicon substrates were firstly irradiated with oxygen ions pulses produced by a Plasma Focus (1 kJ) and then they were thermal treated at different temperatures under oxygen atmosphere. By GI-X-ray diffractometry and atomic force microscopy analyses it has been found that the oxygen addition into the SBT structure favors early perovskite SBT phase crystallization.attracted considerable attention for the development of non-volatile ferroeiectric ramdom access memories (NV-PRAMS) due to its relatively low voltage operation, low leakage current, fast switching and good fatigue resistance with Pt bottom elec- trodes. However, SBT films have a critical problem such as the high processing temperatures ( < 750 OC) that is awkward to be applied to the semiconductor process necessary to the fabrication of FRAhls. The thermal evolution of the SBT films prepared by Chemical Solution Deposition (CSD) showed that firstly an Oxygen deficient fluorite phase is formed at about 550 "C and after, the SBT perovskite phase crystallizes for temperatures higher than 650°C. In order to favor an earlier perovskite crystallization, as-burnt-SBT coated Pt/Ti/Si02/Silicon substrates were firstly irradiated with oxygen ions pulses produced by a Plasma Focus (1 kJ) and then they were thermal treated at different temperatures under oxygen atmosphere. By GI-X-ray diffractometry and atomic force microscopy analyses it has been found that the oxygen addition into the SBT structure favors early perovskite SBT phase crystallization.