摘要:

This paper examines two models proposed by Ishibashi and Fatuzzo in an attempt to relate the switching kinetics they predict. It was found that there does not exist a simple relation between the three adjustible parameters found in each model.

ISSN:1058-4587    

DOI:10.1080/10584589308216694

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The susceptibility profile of thin ferroelectric films was calculated in this paper from Landau phenomenological theory. The dependence of mean susceptibility on the film thicknessLwas discussed. Depending on the parameter δ, the so-called “extrapolation length” which measures the strength of the coupling in the surface layer, two different results are obtained. For δ>0, a size driven phase transition was suggested. Near the critical thicknessLo, the mean dielectric susceptibility can be expressed as Xf' Xb[1 + Co/(L - Lo)]. For δ>0, the mean susceptibility decreases logarithmically with the decrease in film thickness.

ISSN:1058-4587    

DOI:10.1080/10584589308216695

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A generalized ferroelectric capacitor modeling methodology is presented from a theoretical basis through implementation in PSPICE. The approach postulates nonspecific sources of mobile charge as the source of nonideal hysteresis characteristics. These charges are modeled as depletion capacitances in an equivalent circuit model of the ferroelectric capacitor, capable of simulating both AC and DC behavior. A parameter extraction software package is presented, the use of which establishes that the model parameters may be fit to measured hysteresis data with a high degree of accuracy. PSPICE simulation results are then produced which demonstrate the ability to simulate hysteresis and switching behavior. These results may be correlated to measured data to identify specific physical phenomenon, and speed process and device design.

ISSN:1058-4587    

DOI:10.1080/10584589308216696

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Ferroelectric thin films have been integrated with silicon micromechanical structures in the fabrication of microsensor and microactuator structures. Both the piezoelectric and pyroelectric effects in thin films of lead zirconate titanate (Pb(ZrxTi1_x)O3) and lead titanate (PbTiO3) have been used for physical force sensing (pressure sensor), thermal heat sensing (pyroelectric infrared detector) and microactuation (mechanical positioner). Solid-state micromachining is used to form mechanical membranes on a silicon wafer for implementing easily deformable membranes or structures with a low thermal mass. This paper demonstrates the compatible simultaneous integration of 1) sol-gel deposited ferroelectric thin films, 2) surface-machined micromechanical structures and 3) n-well CMOS integrated circuit technologies.

ISSN:1058-4587    

DOI:10.1080/10584589308216697

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Polycrystalline Pb(Zr0.48Ti0.52)O3thin films with the thickness of 0.2 μm on Pt-coated silicon substrates have been prepared by sol-gel process using electrochemically prepared titanium and zirconium solutions in methoxyethanol. Structure, morphology, and electrical properties of the films annealed by usual isothermal annealing for 1 hour and by rapid thermal annealing (RTA) for 1 minute have been studied. In contrast to isothermal annealing RTA results in highly oriented (100) films. This leads to higher dielectric constant (more than twice) of RTA annealed films, but no correlation between degree of orientation and polarization have been observed. Special attention has been paid to capacitance-voltage (CV) characteristics. Some parameters and simple models were introduced for the interpretation of CV data. Thus asymmetry of CV curves indicates that for the films prepared by RTA there exists a problem of disturbed layer formation at the Pt-PZT interface.

ISSN:1058-4587    

DOI:10.1080/10584589308216698

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Perovskite single phase PZT (53/47) thin films were deposited on several potential substrate materials by the sol-gel method and subsequent heat treatment at 700[ddot]C for 10 minutes. (100) lanthanum aluminate substrate was found to be the most effective to produce a PZT (100) epitaxial film. (100) strontium titanate and strontium lanthanum galate also gave very high degree of (100) oriented (96–98%) PZT thin films.

ISSN:1058-4587    

DOI:10.1080/10584589308216699

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The promising application of ferroelectric films as a gate dielectric in some microelectronic devices has been assessed. It is shown that the high dielectric constant of ferroelectrics allows improvement of device performance (amplification and power characteristics of MIS transistors and information amount transferred through the register of CCD). The requirements towards ferroelectric material and ferroelectric-semiconductor interface performance in ferroelectric non-volatile memories have been discussed. On the base of fluctuation theory of surface states it is supposed that the spontaneous polarization may induce additional traps on the ferroelectric-semiconductor interface.

ISSN:1058-4587    

DOI:10.1080/10584589308216700

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Optical bistability in ferroelectric ceramic lead magnesium niobate at room temperature was discovered recently (Chenet al., Applied Physics Letters,60, 332, 1992) and characterized in detail as a function of laser power, sample temperature, pressure and flow rate of the ambient air (Scott and Chen,Integrated Ferroelectrics,1, March 1992). In all these experiments the laser light was incident on the PMN sample with a very fast rise time; thus the switched thermal response of the system was isothermal, with relatively rapid relaxation to steady-state temperatures that are functions of input power. By comparison, in the present study the laser light intensity is ramped up slowly and linearly (slowly compared to the thermal relaxation time of the system, which is typically 200 ms). Under these circumstances the thermal focussing responds adiabatically, and different spatial and temporal patterns are observed. Notable is the hysteretic behavior associated with each switching event; the onset of switching differs for increasing and decreasing laser power by approximately 10–30 mW (10–30 KW/m2), for input powers of 0.1–0.4 W.

ISSN:1058-4587    

DOI:10.1080/10584589308216701

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A computer-controlled dip coating apparatus has been designed and constructed for fabricating dielectric films from precursor solutions. This automated mechanism provided a totally hands-off process by which films of good quality and uniformity were easily and conveniently formed. Fluid mechanics involved in the dip coating process successfully predicted the single-layer film thickness of one dipping and firing cycle, and this thickness was found to be additive to give the final film thickness consisting of multiple such layers. Properties of films of the lanthanum-modified lead zirconate titanate (PLZT) family derived from an acetate precursor system by this process were discussed.

ISSN:1058-4587    

DOI:10.1080/10584589308216702

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:1058-4587    

DOI:10.1080/10584589308216703

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor