摘要:

A stable solution chemistry and a consistent thermal processing route have been developed to produce multi-layer sol-gel lead zirconate titanate (PZT) piezoelectric coatings of high electrical quality. Up to 5 μm thick fully perovskite and piezoelectrically active crack-free coatings with permittivity of 1100–1300 and loss tangents of 1–2% can be produced with careful attention to the choice of titanium and zirconium alkoxide precursors, the choice of solvent, the method of solution preparation, and the thermal processing schedule. The films were deposited on platinized silicon, spinning for 30 seconds at 3000 rpm. Individual layers were dried on a hot plate at 250°C for 30 seconds, fired on a second hot plate at 400°C for 15–60 seconds and annealed in a box furnace at 650°C for 2 minutes. Applications of the films are directed toward piezoelectric transformers, surface acoustic wave devices, and cantilever structures.

ISSN:1058-4587    

DOI:10.1080/10584589908215624

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Initiation of the crystallization of the triple-alkoxy-derived gel films to SrBi2Ta2O9(SBT) perovskite thin films on Pt-passivated Si was addressed. The organic functional group of the triple alkoxide may determine the degree of the hydrolysis and poly-condensation reactions and affect the nucleation sites in the film after annealing. A mixture of water vapor and oxygen flow during the calcination at 250°C promoted the nucleation and growth of SBT below 500°C. It was clarified that the crystallographic orientaion of the SBT thin films has been determined in the primary stage of the crystallization.

ISSN:1058-4587    

DOI:10.1080/10584589908215625

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The crystallinity and the microstructure of Sr0.8Bi2.3Ta2O9(SBT) thin films improved with increasing annealing temperature, and strongly influenced the ferroelectric properties. In addition, the properties of SBT films, such as remanent polarization and leakage current density, are closely related to the film/electrode interface and surface roughness of the underlying electrode. SBT films on Pt/TiO2/SiO2/Si and Pt/ZrO2/SiO2/Si substrates exhibited high remanent polarization, low leakage current density, and low voltage saturation as compared to SBT films on Pt/Ti/SiO2/Si substrates. This is deduced to be related to differences in film orientation, electrode roughness, and out-diffusion of Ti onto the surface of the bottom electrode.

ISSN:1058-4587    

DOI:10.1080/10584589908215626

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

(Pb,La)(Zr,Ti)O3[PLZT] thin films were deposited by chemical solution deposition (CSD) on sputtered Pt/IrO2electrodes on SiO2/Si wafers. A relationship between PLZT grain size and leakage was observed with films of 150 nm thick. Large-grained films showed high leakage, whereas fine-grained films showed low leakage. Limited nucleation sites led to pyrochlore at grain boundaries, which may act as an electrical pathway. Thin CSD PLZT film with lower leakage was prepared by shortening the total pyrolysis time. From these results, pyrolysis time was an important parameter used to control film microstructure and leakage.

ISSN:1058-4587    

DOI:10.1080/10584589908215627

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A series of organic solvents has been used for the preparation of PZT precursor solutions. The stability and the volatility of these PZT precursors have been tested. The results indicate the promising organic solvents are butyl ether, THF, 2-methoxyethyl ether, H(tmhd) and tetraglyme. PZT precursors include Zr(tmhd)4, Zr(OPri)4(HOPri), Zr(OPri)2(tmhd)2, Pb(tmhd)2, Ti(OPri)4and Ti(OPri)2(tmhd)2, which can be dissolved in some special combinations of these organic solvents without losing volatility. However,iso-propanol should be introduced into the PZT precursor solutions if Ti(OPri)4is used as the titanium source. The preparations of PZT thin film via MOCVD have been carried out by using new PZT precursor solutions, and high quality PZT thin films have been obtained.

ISSN:1058-4587    

DOI:10.1080/10584589908215628

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A novel technique was employed to obtain electrical measurements of the high speed switching characteristics of small, discrete, SBT ferroelectric capacitors in response to applied pulses. Switching speed and polarization were directly measured as a function of applied amplitude, pulse width, rise time, and capacitor area. Two different ferroelectric film thicknesses were studied: 175 nm and 240 nm. Measurements were performed using off-wafer circuitry and applied pulses with rise times as fast as 2 ns and pulse widths as narrow as 10 ns on capacitors as small as 4 μm2. A hysteresis loop was also obtained using a 20 MHz driving signal.

ISSN:1058-4587    

DOI:10.1080/10584589908215629

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

As the market for ferroelectric semiconductor memories matures, the FRAM® products manufactured by Ramtron International Corp are moving into mass production. In this scenario, the optimization of the production test flow becomes a key consideration in the profitability of the product. Ramtron International Corp has thus been focussing on developing an optimized production test flow without compromising the final quality of the product.

ISSN:1058-4587    

DOI:10.1080/10584589908215630

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Role of Pt and SRO electrodes in polarization fatigue of PLZT film ferroelectric capacitors is studied. We show that asymmetrical Pt/SRO/PLZT/Pt structure exhibits unusual dependence of the endurance of switching polarization on the driving ac electric field amplitude. Specifically, for high ac electric field amplitude it shows a good switching endurance similar to SRO/PLZT/SRO capacitors, whereas for amplitude lower than 80 kV/cm a pronounced polarization fatigue similar to that of conventional Pt/PLZT/Pt capacitors is observed. Based on the analysis of these results we conclude that the polarization switching endurance under high-amplitude fatiguing cycling is governed only by the top SRO-interface which is not subjected to degradation, whereas the degradation properties of the bottom Pt-interface do not play any role.

ISSN:1058-4587    

DOI:10.1080/10584589908215631

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The hysteresis loop of ferroelectric thin film capacitors, shows sometimes non-saturation effects, i.e. the high electric field parts of the hysteresis loop do not close and the apparent remanent polarization increases with the amplitude of the measurement signal. Several models attributed this effect to the presence of leakage current, but the very high current levels predicted have not been always confirmed by the direct measurements of the DC leakage. Here, we show that the relaxation current, rather than the true DC leakage current can, in these cases, explains the non-saturating behavior. This effect would than not be caused by the movement of free charges, but rather to of the localized ones.

ISSN:1058-4587    

DOI:10.1080/10584589908215632

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Ba1−xPbxTiO3 (BPT) as a thin film system has been developed to investigate the ferroelectric properties respectively the different ferroelectric polarization contributions. BPT has been synthesized using CSD based on metal propionates. The films were deposited on platinum coated silicon wafers and annealed at 750°C. The BPT thin films were characterized with X-ray diffraction and SEM.

ISSN:1058-4587    

DOI:10.1080/10584589908215633

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor