Crystallization of SrBi₂Ta₂O₉ Thin Films in N₂ Ambient by Chemical Solution Deposition Method

Abstract

Structural and electrical properties of SrBi 2 Ta 2 O 9 (SBT) thin films crystallized upon annealing in an N 2 ambient were investigated. These thin films were prepared on Pt/TiO 2 /SiO 2 /Si substrates by the chemical solution deposition (CSD) method. The films crystallized in N 2 after calcination at a high O 2 partial pressure in an N 2 /O 2 mixed ambient showed good ferroelectric properties with remanent polarization 2P r = 13-14 µC/cm 2 , coercive field 2E c = 70-80 kV/cm, and leakage current density less than 1 × 10 −7 A/cm 2 at an applied voltage of 3 V. These ferroelectric properties are the same as those of the SBT crystallized in O 2 . However, the films crystallized in N 2 after calcination at a low O 2 partial pressure in an N 2 /O 2 mixed ambient did not form SBT. TDS data showed that the carbon content of the film calcined in poor O 2 was higher than that of the film calcined in rich O 2 . These results showed that the carbon residue within the film might disturb the formation of SBT.

Kinetics and Mechanisms of MOCVD Processes for the Fabrication of Sr-Containing Films From Sr(hfac)2Tetraglyme Precursor

“…Thus, transparent Sr-containing fluoride glasses (such as SrAlF 5 ) have a key role for optical coatings and luminescent devices − and strontium titanates are of interest for their applications as high-K materials in DRAMs, − while Ln-doped Sr sulfide and Bi−Sr−Ca−Cu mixed oxides 19 are efficient materials for electroluminescent devices and superconducting electronics, respectively. Particular attention has recently been devoted also to SrBi 2 Ta 2 O 9 (SBT) ferroelectric oxides due to the great potentiality for ferroelectric nonvolatile random access memories (FeRAM). − SBT films can be fabricated through several techniques including pulsed laser deposition, , sol−gel, , metal−organic deposition, − and metal−organic chemical vapor deposition (MOCVD). − Among them, MOCVD appears the most viable route for the semiconductor industry because of the superior step coverage compared to that of other deposition techniques.…”

Structural, Electrical, and Ferroelectric Properties of Nb‐Doped Na0.5Bi4.5Ti4O15 Thin Films

“…The BLSF structures are constructed by the stacking of alternating (Bi 2 O 2 ) 2− layers and pseudo‐perovskite blocks [( A n −1 B n O 3 n +1 ) 2− ] along the c ‐axis . In the BLSF family, the thin films of SrBi 2 Ta 2 O 9 , Bi 4 Ti 3 O 12 , and SrBi 4 Ti 4 O 15 have been extensively investigated; however, these materials often show a low remnant polarization . A large polarization is a fundamental requirement for ferroelectric materials intended for use in high‐density data storage devices .…”