Optical Non-Invasive Evaluation of Ferroelectric Films/Memory Capacitors

1994 ◽  
Vol 360 ◽  
Author(s):  
Sarita Thakoor ◽  
A. P. Thakoor ◽  
L. Eric Cross
Keyword(s):  
Thin Films ◽  
High Speed ◽  
Remanent Polarization ◽  
Strong Dependence ◽  
Direct Function ◽  
Ferroelectric Capacitor ◽  
Non Invasive ◽  
On Line ◽  
Ferroelectric Capacitors ◽  
Excellent Tool

AbstractNON-INVASIVE photoresponse (photocurrent/voltage, reflectance and transmittance) from ferroelectric thin films and memory capacitors, with its strong dependence not only on the remanent polarization, but also on the film microstructure, crystal orientation, and nature of the interfaces (state of formation/degradation, etc.) offers an excellent “tool” for probing the ferroelectric capacitors at virtually any stage of fabrication, including on-line quality control. In fact, simultaneous measurement of spectral photoresponse and spectral reflectance, as a distinctive signature of the device probed, is an ideal, high speed, non-invasive means of evaluation for such thin films at high spatial resolution (∼ 100 nm) using beam scanning. This paper discusses three aspects of such evaluation. First, the spectral transmittance of the film as a direct function of the microstructure, second, the use of band-gap illumination (365 nm) to condition a fatigued capacitor; and third, the optical E field interaction with the ferroelectric capacitor, yielding a high speed photoresponse which is related to the remanent polarization and the operational history (status of internal fields) of the ferroelectric capacitor. Combined, these different kinds of photoresponses provide a good signature of the device quality.

Epitaxial LaNiO3Interlayers for Ferroelectric Memory Structures

1994 ◽  
Vol 341 ◽  
Author(s):  
J. D. Klein ◽  
A. Yen ◽  
S. L. Clauson
Keyword(s):  
Thin Films ◽  
Nonvolatile Memory ◽  
Remanent Polarization ◽  
Long Term Memory ◽  
Metallic Contact ◽  
Ferroelectric Capacitor ◽  
Wide Range ◽  
Memory Applications ◽  
Ferroelectric Capacitors

AbstractLaNiO3 thin films were utilized as metallic contact layers in ferroelectric capacitors. The LaNiO3 films were probably epitaxial when deposited atop (100) LaAlO3 substrates. They exhibited metallic resistivity over a wide range of temperature and oxygen partial pressure. Subsequent deposition of PZT and LaNiO3 thin films atop LaNiO3/LaAlO3 allowed realization of parallel-plate ferroelectric capacitor structures. The suitability of such devices for nonvolatile memory applications was surveyed through pulsed voltage testing. The observed 1-second remanent polarization exceeded 18 μC/cm2. Long-term memory was demonstrated for up to sixteen hours. No decrease in remanent polarization was apparent after more than 109 switching cycles.

Process Integration for Nonvolatile Ferroelectric Memory Fabrication

MRS Bulletin ◽  
1996 ◽  
Vol 21 (6) ◽  
pp. 55-58 ◽  
Author(s):  
Robert E. Jones ◽  
Seshu B. Desu
Keyword(s):  
Computer Technology ◽  
Remanent Polarization ◽  
Process Integration ◽  
Digital Data ◽  
Ferroelectric Capacitor ◽  
The Core ◽  
Early Computer ◽  
Ferroelectric Layer ◽  
Ferroelectric Memory ◽  
Ferroelectric Capacitors

The remanent-polarization states of ferroelectric capacitors have long been of interest for nonvolatile storage of digital data. A simple memory array can be formed by perpendicular rows and columns of conductors with a ferroelectric capacitor at each crosspoint. In the simplest geometry, these conductors also are the capacitor electrodes on either side of a ferroelectric layer. Each capacitor represents one bit of digital data. If a voltage of V0 is required to write a capacitor, then data can be written to a specific bit by applying V0/2 and –V0/2 to the appropriate row and column. Such ferroelectric memory arrays were constructed as early as the 1950s. However, due to the breath of the ferroelectric transition, they were not successful because during the write of a specific capacitor, the V0/2 voltage signals disturb the polarization in other capacitors. This is in contrast to the successful use of the analogous ferromagnetic crosspoint arrays, which are familiar as the core memories of early computer technology.

Optical Band Gap Implications for Ferroelectric Memory Applications

1994 ◽  
Vol 361 ◽  
Author(s):  
J.D. Klein ◽  
S.L. Clauson
Keyword(s):  
Thin Films ◽  
Nonvolatile Memory ◽  
Remanent Polarization ◽  
Long Term Memory ◽  
X Ray Diffraction ◽  
Ferroelectric Capacitor ◽  
Wide Range ◽  
Ferroelectric Memory ◽  
Memory Applications

Metallic perovskite contact layers enable fatigue-resistant ferroelectric memory capacitors to be obtained. LaNiO3 films atop (100) LaAlO3 substrates exhibit metallic resistivity over a wide range of temperature and oxygen partial pressure. Subsequent deposition of PZT and LaNiO3 thin films atop LaNiO3/LaAlO3 provides parallel-plate ferroelectric capacitor structures. However, the quality of the PZT thin films cannot be reliably indicated by conventional means such as x-ray diffraction. Optical properties of the PZT layers were examined to discern differences in otherwise similar films. The suitability of Au/LaNiO3/PZT/LaNiO3/LaAlO3 devices for nonvolatile memory applications was surveyed through pulsed voltage testing. Observed 1-second remanent polarization (PR [1 sec]) exceeded 35μC/cm2. Long-term memory was demonstrated for up to sixteen hours. No decrease in remanent polarization was apparent after more than 2 × 1010 switching cycles.

Electrical Measurement of Ferroelectric Capacitors for Non-Volatile Memory Applications

1990 ◽  
Vol 200 ◽  
Author(s):  
Norman Abt
Keyword(s):  
Remanent Polarization ◽  
Cmos Technology ◽  
Electrical Measurement ◽  
Ferroelectric Capacitor ◽  
Non Volatile Memory ◽  
In Series ◽  
Volatile Memory ◽  
Memory Applications ◽  
Silicon Cmos ◽  
Ferroelectric Capacitors

ABSTRACTModified lead titanate ferroelectdc thin films are currently utilized in conjunction with silicon CMOS technology for non-volatile memory applications. The electrical measurement of ferroelectric films has been common practice for many years but the parameters necessary for optimizing their use as memory have not been routinely recorded. Remanent polarization, spontaneous polarization and their change through fatigue and ageing are still the dominant parameters but the pulsing conditions of interest are driven by the circuit requirements. The operation of a memory circuit will be discussed along with implications for testing. Memory is written by applying a pulse to the capacitor. It is read by applying a pulse and sensing whether or not the polarization switched. Read and write pulses will apply different voltages to the ferroelectric capacitor in the circuit because a sense capacitor will be in series with it during the read. A new test, pulsed hysteresis, which is based on circuit operation will be presented. Parameter space of interest will also be discussed.

Automatic Calibration of Clamp-On Ultrasonic Flowmeter Based on Fieldbus Control System

2011 ◽  
Vol 301-303 ◽  
pp. 1730-1734
Author(s):  
Qing Qiang Hou ◽  
Yong Mei Huang ◽  
Zhi Liang Zhang ◽  
Bin Sun
Keyword(s):  
Control System ◽  
High Speed ◽  
Electromagnetic Flowmeter ◽  
Ultrasonic Flowmeter ◽  
Practical Significance ◽  
Automatic Calibration ◽  
Calibration System ◽  
Non Invasive ◽  
Comparison Results ◽  
On Line

In practical application, some flowmeters are not allowed to be calibrated off-line periodically, thus on-line calibration is necessary to be implemented in workplace [1]. As a non-invasive flowmeter, the clamp-on ultrasonic flowmeters are widely used in on-line calibration system. As a master flowmeter, ultrasonic flowmeters must be calibrated before or during using. Based on multiple fieldbus control system, an automatic calibration system for the ultrasonic flowmeter was designed. The comparison results between ultrasonic and electromagnetic flowmeter obtained during the process of calibrating manifest that the automatic calibration system is effective and reliable. Because of the good interoperability of the multiple fieldbus, other flowmeters with different protocols can be connected into this system easily. With the high speed development of fieldbus technology, this has great practical significance in flowmeter calibration.

Transient Behavior of the Polarization in Ferroelectric Thin Film Capacitors

2000 ◽  
Vol 655 ◽  
Author(s):  
Oliver Lohse ◽  
Michael Grossmann ◽  
Dierk Bolten ◽  
Ulrich Boettger ◽  
Rainer Waser
Keyword(s):  
Thin Films ◽  
Low Voltage ◽  
Ferroelectric Thin Film ◽  
Transient Behavior ◽  
Polarization Switching ◽  
Switching Behavior ◽  
Ferroelectric Capacitor ◽  
Low Voltage Operation ◽  
High K Materials ◽  
Ferroelectric Capacitors

AbstractThe understanding of the polarization switching process of ferroelectric capacitors is highly relevant for the development and optimization of FeRAM devices. We report on the characterization of Pb(Zr,Ti)O3 thin films which have been studied by means of dedicated rectangle pulse measurements. Decreasing the voltage level of the excitation pulses decelerates the polarization switching significantly to the range of milliseconds and reduces the switchable polarization. In this work the influence of niobium (Nb) doping on the switching properties of PZT thin films prepared by CSD are investigated to reach the aspired conditions of low voltage operation, read and write access pulses in the range of nanoseconds. For the implementation of the transient behavior of ferroelectric capacitors in circuit design and simulation tools it is necessary to develop a model which precisely describes the polarization hysteresis, the pulse switching behavior as well as the small signal capacitance. The fundamental considerations for this model are presented, based on an ideal ferroelectric capacitor, taking into account the Curie-von Schweidler behavior. The latter is observed in non-ferroelectric high-K materials as well as in ferroelectric thin films.

The on-line use of histogram data for high-speed correction and alignment of electron microscope images

1984 ◽  
Vol 42 ◽  
pp. 556-557
Author(s):  
William Krakow
Keyword(s):  
Power Spectrum ◽  
High Speed ◽  
Direct Memory Access ◽  
Digital Television ◽  
Contrast Transfer Function ◽  
The Past ◽  
High Resolution Tem ◽  
On Line ◽  
Correction Of Astigmatism ◽  
The Fourier Transform

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.

scholarly journals PANI-Based Wearable Electrochemical Sensor for pH Sweat Monitoring

Chemosensors ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 169
Author(s):  
Francesca Mazzara ◽  
Bernardo Patella ◽  
Chiara D’Agostino ◽  
Maria Giuseppina Bruno ◽  
Sonia Carbone ◽  
...  
Keyword(s):  
Thin Films ◽  
Indium Tin Oxide ◽  
Electrochemical Sensors ◽  
Flexible Substrate ◽  
Sensor Performance ◽  
Non Invasive ◽  
Static Contact ◽  
Sweat Sample ◽  
Constant Potential ◽  
Interference Tests

Nowadays, we are assisting in the exceptional growth in research relating to the development of wearable devices for sweat analysis. Sweat is a biofluid that contains useful health information and allows a non-invasive, continuous and comfortable collection. For this reason, it is an excellent biofluid for the detection of different analytes. In this work, electrochemical sensors based on polyaniline thin films deposited on the flexible substrate polyethylene terephthalate coated with indium tin oxide were studied. Polyaniline thin films were abstained by the potentiostatic deposition technique, applying a potential of +2 V vs. SCE for 90 s. To improve the sensor performance, the electronic substrate was modified with reduced graphene oxide, obtained at a constant potential of −0.8 V vs. SCE for 200 s, and then polyaniline thin films were electrodeposited on top of the as-deposited substrate. All samples were characterized by XRD, SEM, EDS, static contact angle and FT-IR/ATR analysis to correlate the physical-chemical features with the performance of the sensors. The obtained electrodes were tested as pH sensors in the range from 2 to 8, showing good behavior, with a sensitivity of 62.3 mV/pH, very close to a Nernstian response, and a reproducibility of 3.8%. Interference tests, in the presence of competing ions, aimed to verify the selectivity, were also performed. Finally, a real sweat sample was collected, and the sweat pH was quantified with both the proposed sensor and a commercial pH meter, showing an excellent concordance.

Microwave On-Line Measurements on Conveyed Products Application to Paper and Wood Industries

1994 ◽  
Vol 347 ◽  
Author(s):  
J.Ch. Bolomey ◽  
G. Cottard ◽  
P. Berthaud ◽  
A. Lemaitre ◽  
J. F. Portala
Keyword(s):  
High Speed ◽  
Transformation Process ◽  
Wood Material ◽  
Quantitative Measurements ◽  
On Line ◽  
Phase Data ◽  
Polynomial Expansions ◽  
Physical Quantities ◽  
Data Calibration

ABSTRACTMicrowave multiport sensors have been shown to provide some unique capabilities to achieve real-time testing of products conveyed at high speed. In many applications, quantitative measurements of physical quantities such as moisture content, density, etc… are required, either to guarantee reliable production or to optimally control a fabrication/transformation process. In this paper, different ways of extracting such physical quantities from microwave measurements performed by multiport sensors are presented. Model approaches are used, based on polynomial expansions of the physical quantities to be measured as a function of the microwave amplitude and phase data. Calibration procedures have been investigated for both paper and wood material samples. Comparisons between in-situ, microwave and conventional, measurements are analysed.

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