Bo Jiang

Bipolar and unipolar resistive switching behaviors of sol–gel-derived SrTiO3 thin films with different compliance currents

The SrTiO3 (STO) thin fi lms on aP t/Ti/SiO2/Si substrate were synthesized using a sol–gel method to form a metal–insulator–metal structure. This device shows the bipolar resistance switching (BRS) behavior for a compliance current Icc of less than 0.1 mA but exhibits soft breakdown at a higher level of compliance current. A transition from the BRS behavior to the stable unipolar resistive switching behavior (URS) was also observed. We found that the BRS behavior may be controlled by the structure interface while the URS behavior is likely bulk controlled. Our study indicates that the external compliance current is a key factor in resistance switching phenomenon of STO thin films. (Some figures in this article are in colour only in the electronic version)

Large memory window and good retention characteristics of ferroelectric-gate field-effect transistor with Pt/Bi3.4Ce0.6Ti3O12/CeO2/Si structure

Bi4?xCexTi3 O12(x?=?0.0, 0.4, 0.6 and 1.0) ferroelectric-thin films were fabricated by chemical solution deposition. Among these thin film samples, Bi3.4Ce0.6Ti3O12 (BCT) exhibits the best ferroelectric property. An n-channel metal?ferroelectric?insulator?silicon (MFIS) ferroelectric-gate field-effect transistor (FeFET) with Pt/BCT/CeO2/Si structure was fabricated and characterized. Due to the relatively good interface properties between the insulator layer (CeO2) and ferroelectric-gate layer (BCT), the device shows a nearly unchanged memory window of about 3.2?V after a 24?h retention test and a field-effect mobility of approximately 24.6?cm2?V?1?s?1. These results suggest that the Pt/BCT/CeO2/Si FeFET is suitable for high-performance ferroelectric memory application.

The influence of ferroelectric–electrode interface layer on the electrical characteristics of negative-capacitance ferroelectric double-gate field-effect transistors

The surface potential and subthreshold characteristics in negative capacitance (NC) double-gate ferroelectric field-effect transistor (FeFET) were investigated by considering the metal–ferroelectric interface layer. The derived results indicates that the negative capacitance regime which allows for amplified surface potential and steeper subthreshold characteristics were significantly affected by the interface layer. This imposes a severe limit to the step-up conversion capability and steeper subthreshold (<60 mV/dec) obtainable in the device. These results may provide some insight into the design and performance improvement for the low power dissipation FeFETs.

Influence of pyrolysis temperature on ferroelectric properties of La and Mn co-doped BiFeO3 thin films

Abstract Bi0.9La0.1Fe0.95Mn0.05O3 (BLFMO) ferroelectric thin films were fabricated on Pt/Ti/SiO2/Si/substrates by the sol-gel process at different pyrolysis temperatures. The mass loss of BLFMO powder was investigated by thermo gravimetry analyser (TGA), and the polycrystalline structure and smooth surface of BLFMO thin films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The remnant polarization (Pr) of the BLFMO films pyrolyzed at 420°C is 21.2 μC/cm2 at the coercive field (Ec) of 99 kV/cm and the leakage current density is 7.1×10−3 A/cm2, which indicates that the BLFMO thin films display relatively good ferroelectric property at this temperature.

Fabrication and Electrical Properties of P(VDF-TrFE)/Bi3.5Nd0.5Ti3O12 Bi-Layer Composite Ferroelectric Thin Films

The microstructure and electrical properties of P(VDF-TrFE)/Bi3.5Nd0.5Ti3O12 bi-layer composite ferroelectric thin films deposited on Pt/Ti/SiO2/Si using two successive spin coatings were investigated. It shows the pores in Bi3.5Nd0.5Ti3O12 (BNT) films were effectively suppressed by the presence of P(VDF-TrFE) copolymer films by SEM. The ferroelectric, leakage and dielectric properties of the thin films with different thickness ratio of P(VDF-TrFE) and BNT thin films were measured. With increasing the thickness of P(VDF-TrFE), the remnant polarization, coercive electric field, leakage current density and dielectric constant of thin films were all decreased (except pure P(VDF-TrFE) thin film). Results indicate that the key electrical properties were improved effectively by a little loss of the remnant polarization, which infers potential application in the filed of ferroelectric memory.