摘要:

A somewhat qualitative review of leakage currents J(V,t) in perovskite oxides is presented. It is stressed that space-charge-limited currents (SCLCs) are not alternatives to ionic conduction, Schottky emission, Poole-Frenkel, or Fowler-Nordheim tunneling, but can occur whenever currents due to any of those mechanisms reach a certain threshold and are no longer limited by the details of the metal electrode-ferroelectric interface. Standard metal-semiconductor band models that exclude surface states fail qualitatively to account for the experimental dependences of leakage currents and breakdown voltages on electrode work function; the correct model is metal-n-p-n-metal, with surface donor-state trapping. A discussion of conduction properties in these materials is presented from an ionic conductor viewpoint.

ISSN:1058-4587    

DOI:10.1080/10584589508012900

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The controllability of PZT film properties and the possibility of the scaling up the MOCVD to the commercial based production were briefly reviewed. The film composition and crystalline phase of the PZT films were easily controlled using the MOCVD process. The electrical properties were also controlled by changing the growth parameters. A low processing temperature was achieved using a new Pb precursor, tryethyl n-pentoxy lead. Large area growth of PZT and PLZT films on a 6–8 inch wafer was also achieved.

ISSN:1058-4587    

DOI:10.1080/10584589508012901

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

PZT thin films with a uniform distribution of components were prepared by plasma enhanced chemical vapor deposition (PECVD) using Pb(C2H5)4, Z (O-i-C4H9)4, Ti(O-i-C3H7)4, and oxygen. The crystallization of films was occure after annealing in the temperature range between 450 and 550°C under O2ambient for 1 hr. The significant change of Pb concentration in PECVD PZT thin films was not observed in the relation to annealing temperature and time. The dielectric constant PECVD PZT thin films increased with the Ti content, showed the maximum value in the vicinity of morphotropic phase boundary (MPB) composition of PZT material, and decreased with the Ti content. The leakage current density of PZT (65/35) thin film of 180 nm in thickness was 3·37 × 10−7A/cm2at the applied voltage of 3 V. Remanent polarization increased with increasing of Zr content in the film and coercive field was nearly independent of the composition. The typical values of electrical properties were εr= 570,Ec= 90 kV/cm, andPr= 19 μC/cm2in the PECVD PZT (54/46) thin film of 220 nm in thickness.

ISSN:1058-4587    

DOI:10.1080/10584589508012902

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Parameters for the design of neural prostheses are discussed.

ISSN:1058-4587    

DOI:10.1080/10584589508012903

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

During high temperature processing an interface layer is formed between the PZT and Ti substrate by the oxidation of the substrate. The effects on the measured electrical properties of PZT are investigated using dielectric, IV and CV analysis.

ISSN:1058-4587    

DOI:10.1080/10584589508012904

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The theory of the frequency response of thin ferroelectric films is described, using the Transverse Ising Model. Modes are calculated for a 10-layer film, in which the surface layer has either an enhanced or reduced coupling. Typical FIR reflectivity spectra are shown.

ISSN:1058-4587    

DOI:10.1080/10584589508012905

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The D-E hysteresis loop of ferroelectrics is theoretically studied on the basis of the Avrami model, extended for the case of applied field dependent sidewise velocity. The exponent for the frequency dependence of the extended volume is obtained. The exponent of the area of hysteresis loop, with respect to the frequncy, is also obtained.

ISSN:1058-4587    

DOI:10.1080/10584589508012906

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Ferroelectric Pb(Zr,Ti)O3(PZT) thin films were prepared by pulsed excimer laser deposition on Silicon-on-Insulator (SOI) substrates with and without an electrode. Their properties can be improved by rapid thermal annealing, based on the structural and interfacial characteristics analysis by X-ray diffraction, Rutherford backscattering spectroscopy and automatic spreading resistance measurements. The thin films were revealed of to be polycrystalline perovskite structure with mainly ⟨100⟩ and ⟨110⟩ orientations; the crystallite size and the structure are dependent on the annealing time. The PZT thin films did not interact with the top silicon layers of SOI, and the composition was on the tetragonal side of the morphotropic phase boundary in the PbTiO3-PbZrO3phase diagram.

ISSN:1058-4587    

DOI:10.1080/10584589508012907

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Pb(Zr,Ti)O3thin films were prepared by ArF excimer laser deposition on silicon and Pt-coated silicon substrates, and then were treated by rapid thermal annealing. The dependence of perovskite/pyrochlore phase formation on annealing conditions was investigated. The results show that the formation of perovskite phase or pyrochlore phase in the films was not only dependent on the heat treatment temperature, but also dependent on the heat treatment time. A wide range operational window of heat treatment time and temperature for obtaining single phase perovskite Pb(Zr,Ti)O3thin films was given, and the films were analyzed by Rutherford backscattering spectroscopy to explain this phase transition.

ISSN:1058-4587    

DOI:10.1080/10584589508012908

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Nano-crystalline Pb0·72La0·28TiO3(PLT28) thin films were prepared on glass substrate by RF magnetron sputtering using the sequence of post-deposition annealing process. 150 to 200nm thick films were found to be comprised of 5nm grains in the perovskite structure. The effective birefringence shift in the nano-PLT films as a function of applied electric field exhibits a quadratic electro-optical behavior. The hysteresis measurement indicated that the films display slim-loop character. Experimental results showed that the nano PLT film is an electric fieldinduced ferroelectric.

ISSN:1058-4587    

DOI:10.1080/10584589508012909

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor