Characteristics of Metal/Ferroelectric/Insulator/Semiconductor Structure Using SrBi ₂Ta ₂O ₉ as the Ferroelectric Material

Abstract

We fabricated a metal/ferroelectric/insulator/semiconductor (MFIS) structure using SrBi2Ta2O9 (SBT) as the ferroelectric material for the first time. The SBT thin film on CeO2/Si (100) had (105), (110) and (200) orientation. Threshold hysteresis (called “memory window”) was observed in the capacitance-voltage ( C–V ) characteristics of this sample. The memory window was about 0.5 V. From the calculation of the C–V characteristics, it is estimated that the density of surface states at the CeO2/Si interface increases upon deposition of SBT. By X-ray diffraction (XRD) analysis, diffusion of Si to the surface of SBT was detected. In order to prevent such diffusion it may be necessary to reduce the firing temperature.

INTERFACE STUDIES AND ELECTRONIC PROPERTIES OF SILICON BASED Nd-DOPED BISMUTH TITANATE

“…Bi(C 5 H 11 COO) 3 , Nd(CH 3 COO) 3 , Ti(C 4 H 9 O) 4 were used as the starting materials with CH 3 COOH, H 2 N(CH 2 ) 2 OH, CH 3 OCH 2 CH 2 OH as the main solvent. More than 10 mol% of Bismuth nitrate was introduced to compensate the Bi loss during the thermal annealing process.…”

“…Si 3 N 4 layer has been carefully investigated, because of the relatively high dielectric constant and good oxygen isolation properties [2]. CeO 2 buffer layer shows chemical stable and good epitaxial growth on the Si substrate, but poor resistance properties between the ferroelectric film and the Si substrate when the anneal temperature is higher than 800 • [3,4].…”

Controllable capacitance–voltage hysteresis width in the aluminum–cerium-dioxide–silicon metal–insulator–semiconductor structure: Application to nonvolatile memory devices without ferroelectrics

“…[1][2][3] For the successful operation of MFSFETs as nonvolatile devices, it is prerequisite that the MFS capacitor, which consists of a metal, a ferroelectric, and a semiconductor, shows hysteresis in the capacitance-voltage (C -V) plot, which is caused due to the remnant polarization of the ferroelectric. Most of the recent studies on the MFSFET focus on the achievement of reliable C -V hystereses with wide width using the metalferroelectric-semiconductor structure.…”

“…Pb͑Zr, Ti͒O 3 and SrBi 2 Ta 5 O 9 are widely used ferroelectric materials for MFSFETs. 2,3 The ferroelectric properties of these materials depend greatly on the composition of the materials. However, these materials are quaternary materials, and it is quite challenging to deposit thin films of these quaternary materials with the right compositions.…”

“…For the sample with 3000 Å CeO 2 , the hysteresis width was as high as ϳ1.8 V, which is comparable to or larger than hysteresis width values obtained in metal-ferroelectricsemiconductor structures. 2,3 Figures 3͑a͒ and 3͑b͒ show TEM images of interfacial structures of CeO 2 (300 Å)/Si and CeO 2 (3000 Å)/Si, respectively, after annealing. Between the CeO 2 layers and Si͑100͒ substrates, there exist amorphous SiO 2 layers.…”