Polarization Switching Behavior of Ferroelectric (NH4)0.39K0.61NO3 Films

2010 ◽  
Vol 93-94 ◽  
pp. 49-58 ◽  
Author(s):  
Navneet Dabra ◽  
Jasbir S. Hundal

The polarization switching transients of spray-deposited ferroelectric (NH4)0.39K0.61NO3 (NKN) films have been investigated. Modified Sawyer-Tower circuit has been used to trace the hysteresis loop (P-E). The value of maximum polarization, Ps and coercive field, Ec was found to be 6.58 µC/cm2 and 4.10 kV/cm respectively. The polarization fatigue study has been carried out. The experimental polarization switching transients were fitted well with the Kolmogorov-Avrami-Ishibashi (KAI) nucleation theory The maximum polarization switching current (imax) and maximum switching time (tmax) have been measured as a function of the applied field. The activation field (), dimensionality (n) and switching time have been determined by employing the KAI model to the experimental switching transients. The atomic force microscopy (AFM) has been employed to estimate the grain size (~ 72 nm) and root mean square roughness (rms) (~ 130nm) of the (NH4)0.39K0.61NO3 films and has been correlated with the switching properties.

2009 ◽  
Vol 615-617 ◽  
pp. 643-646 ◽  
Author(s):  
Akimasa Kinoshita ◽  
Takashi Nishi ◽  
Takasumi Ohyanagi ◽  
Tsutomu Yatsuo ◽  
Kenji Fukuda ◽  
...  

The Ti/4H-SiC Schottky barrier diodes with a field limiting ring (FLR) structure are fabricated. Two types of SBDs are prepared; one (SBD-A) is covered and another (SBD-B) isn’t covered with a carbon cap during high temperature annealing after ion implantation. The breakdown voltage at room temperature for SBD-A and SBD-B are 1400 V and 1000 V, respectively. The breakdown for both SBDs occurs due to an avalanche breakdown. The light emission images are obtained at the breakdown voltage by photo emission microscope (PEM). The light emission is observed along an FLR of the SBD-A as designed. On the other hand, the spot of light emission is observed on a FLR structure of the SBD-B. This light emission spot indicates that leakage current is concentrated because an electrical field concentration is generated at this one for the SBD-B. The root-mean-square roughness of the Al-implanted region on the FLR structure calculated from the atomic force microscopy (AFM) images for the SBD-A and the SBD-B are 0.697 nm and 5.58 nm, respectively. Therefore it is considered that large surface roughness on the FLR decreases breakdown voltage of SBD because an electrical field concentration is generated at a spot.


2014 ◽  
Vol 925 ◽  
pp. 92-95
Author(s):  
Zaliman Sauli ◽  
Vithyacharan Retnasamy ◽  
Uda Hashim ◽  
Steven Taniselass ◽  
Moganraj Palianysamy ◽  
...  

This study reports on the preliminary investigations on the effect of Reactive Ion Etch (RIE) parameters on the surface characteristics of Al bond pad. Investigation is done employing Design of Experiment (DOE) method. Quantity of Oxygen, Argon, ICP power and BIAS power were varied to get 16 sets of recipes. This provides 16 samples with different combination of RIE parameters. Surface characteristics of the samples were analyzed using Atomic Force Microscopy (AFM).Data collected were in terms of Surface Roughness (RA), Peak Vs Valley (P-V) and Surface Root-Mean-Square Roughness (RMS). Result shows that combination of these RIE parameters does not vastly affect the surface characteristics of the Al bond pad.


2000 ◽  
Vol 629 ◽  
Author(s):  
Jonathan S. Schulze ◽  
Timothy P. Lodge ◽  
Christopher W. Macosko

ABSTRACTThe reaction of perdeuterated amino-terminal polystyrene (dPS-NH2) with anhydrideterminal poly(methyl methacrylate) (PMMA-anh) at a PS/PMMA interface has been observed with forward recoil spectrometry (FRES). Bilayer samples were constructed by placing thin films of PS containing ∼8.5 wt % dPS-NH2 on a PMMA-anh layer. Significant reaction was observed only after annealing the samples at 174°C for several hours, a time scale at least two orders of magnitude greater than the time required for the dPS-NH2 chains to diffuse through the bulk PS layer. The topography of the interfacial region as copolymer formed was measured using atomic force microscopy (AFM). Roughening of the PS/PMMA interface was observed to varying degrees in all annealed samples. Furthermore, the extent of this roughening was found to depend on the PS matrix molecular weight. Reaction in the samples with a high molecular weight PS matrix resulted in a root mean square roughness approximately equal to the radius of gyration Rg of the copolymer. However, approximately twice as much roughening was observed in the low molecular weight PS matrix. This study reveals how the molecular weight of one of the phases can affect the rate of reaction at a polymer/polymer interface.


2001 ◽  
Vol 693 ◽  
Author(s):  
Amy M. Roskowski ◽  
Peter Q. Miraglia ◽  
Edward A. Preble ◽  
Sven Einfeldt ◽  
Robert F. Davis

AbstractA growth process route that results in thin film GaN templates with a smooth surface morphology at the optimum temperature of 1020°C has been developed. Atomic force microscopy (AFM) reveals hillocks on films grown above 1020°C. Hillocks resulted from the rotation of heterogeneous steps formed at pure screw or mixed dislocations which terminated on the (0001) surface. Growth of the latter feature was controlled kinetically by temperature through adatom diffusion. The 106 cm-2 density of the hillocks was reduced through growth on thick GaN templates and regions of pendeo-epitaxy (PE) overgrowth with lower pure screw or mixed dislocations. Smooth PE surfaces were obtained at temperatures that reduced the lateral to vertical growth rate but also retarded hillock growth that originated in the stripe regions. The (1120 ) PE sidewall surface was atomically smooth, with a root mean square roughness value of 0.17 nm which was the noise limited resolution of the AFM measurements.


Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Joel Molina-Reyes ◽  
Luis Hernandez-Martinez

We present the resistive switching characteristics of Metal-Insulator-Metal (MIM) devices based on amorphous Al2O3 which is deposited by Atomic Layer Deposition (ALD). A maximum processing temperature for this memory device is 300°C, making it ideal for Back-End-of-Line (BEOL) processing. Although some variations in the forming, set, and reset voltages (VFORM, VSET, and VRESET) are obtained for many of the measured MIM devices (mainly due to roughness variations of the MIM interfaces as observed after atomic-force microscopy analysis), the memristor effect has been obtained after cyclic I-V measurements. These resistive transitions in the metal oxide occur for both bipolar and unipolar conditions, while the IOFF/ION ratio is around 4–6 orders of magnitude and is formed at gate voltages of Vg<4 V. In unipolar mode, a gradual reduction in VSET is observed and is related to combined (a) incomplete dissolution of conductive filaments (made of oxygen vacancies and metal ions) which leaves some residuals and (b) thickening of chemically reduced Al2O3 during localized Joule heating. This is important because, by analyzing the macroscopic resistive switching behavior of this MIM structure, we could indirectly relate it to microscopic and/or nanoscopic phenomena responsible for the physical mechanism upon which most of these devices operate.


2011 ◽  
Vol 239-242 ◽  
pp. 2981-2985
Author(s):  
Liang Xian Huang ◽  
Xi Ya Zhang ◽  
Qiu Feng An

A novel polysiloxane bearing (N,N)-dimethyl-γ-aminopropyl-γ-aminopropyl side groups(ASO-2) was synthesized by copolymerization of octamethylcyclotetrasiloxane with (N,N)-dimethyl-γ-aminopropyl-γ-aminopropyl methyl dimethoxysilane and hexamethyldisiloxane. Chemical structure, film morphology and the softening fabric property of ASO-2 were characterized and investigated by IR, 1H-NMR, SEM, atomic force microscope(AFM) and Kawabata evaluation system(KES).The experiment results indicate that ASO-2 can form a hydrophobic film on both the cotton fiber and silicon wafer surface. The ASO-2 film relatively exhibits a non-homogeneous structure and uneven morphology in its AFM images. Consequently, in 2 μm2 scanning field, the root mean square roughness of ASO-2 film reaches to 0.226 nm, which is 2.69 times rougher as compared with that of N-β-aminoethyl-γ-aminopropyl polysiloxane (ASO-1) film. Application experiments indicate though the tactile of ASO-2 imparted on 100% cotton is somewhat rougher than that of ASO-1, the whiteness and wettability of the cotton treated by ASO-2 are better than those by ASO-1.


2002 ◽  
Vol 48 (2-3) ◽  
pp. 249-253 ◽  
Author(s):  
B Wang ◽  
K.W Kwok ◽  
H.L.W Chan ◽  
C.L Choy ◽  
K.Y Tong ◽  
...  

2009 ◽  
Vol 421-422 ◽  
pp. 143-147
Author(s):  
Masafumi Kobune ◽  
Hideto Tada ◽  
Hisashi Oshima ◽  
Daisuke Horii ◽  
Akihiro Tamura ◽  
...  

After depositing amorphous (Bi0.5La0.5)(Ni0.5Ti0.5)O3 (BLNT) films on BLNT seed layer/Pt(100)/ MgO(100) substrates by room-temperature sputtering, the crystallization of the perovskite-struc- tured films has been tried by hot isostatic pressing (HIP). The samples with a single-phase perovskite structure HIP-treated at 800°C for 1 h under gas pressures of 0.51.0 MPa showed good crystallinity of  = 0.960.98 without accompanying the precipitation of the secondary phase. It was confirmed that a large root mean square roughness value of 44.2 nm for the sample HIP-treated at 800°C for 1 h under gas pressure of 0.1 MPa is due to innumerable Bi4Ti3O12-like rod-shaped grains precipitated in the film surface, based on atomic force microscopy. It is shown that the BLNT sample HIP-treated at 800°C for 1 h under gas pressure of 1.0 MPa exhibits the best hysteresis loop shape with a remanent polarization of Pr = 5 C/cm2 and a coercive field of Ec = 150 kV/cm of the six.


Author(s):  
Олег Васильевич Девицкий

Методом импульсного лазерного напыления в атмосфере аргоно-азотной газовой смеси из мишени InGaAs впервые были получены тонкие пленки InGaAsN на подложках GaAs и Si. Мишень lnGaAs формировалась методом одноосного прессования из порошков GaAs и lnAs. Методами атомно силовой микроскопии и рентгеновской дифракции исследованы морфология поверхности и структура данных тонких пленок. Показано, что пленки InGaAsN на Si имеют средний размер кристалла 0,93 нм, а пленки и InGaAsN на GaAs - 0,99 нм. Определено, что уменьшение давления аргоно-азотной смеси при импульсном лазерном напылении тонких пленок InGaAsN на подложках GaAs и Si приводит к снижению значения среднеквадратичной шероховатости поверхности. Наименьшую среднеквадратическую шероховатость равную 0,25 нм имела тонкая пленка InGaAsN на подложке GaAs, полученная в вакууме, наибольшую среднеквадратическую шероховатость имела тонкая пленка InGaAsN на подложке Si, полученная при давления аргоно-азотной смеси от 10 Па - 19,37 нм. By the method of pulsed laser deposition in atmosphere of an argon-nitrogen gas mixture, for the first time thin InGaAsN films on GaAs and Si substrates were obtained from the InGaAs target. The InGaAs target was formed by uniaxial pressing from GaAs and InAs powders. The surface morphology and structure of these thin films are studied by atomic force microscopy and X-ray diffraction. It is shown that InGaAsN films on Si have an average crystal size of 0,93 nm, and InGaAsN films on GaAs of 0,99 nm. It is determined that a decrease in the pressure of an argon-nitrogen mixture during pulsed laser deposition of thin InGaAsN films on GaAs and Si substrates leads to a decrease in the value of the root- mean-square roughness of the surface. The smallest root-mean-square roughness equal to 0,25 nm had a thin InGaAsN film on a GaAs substrate obtained in vacuum, the largest root-mean- square roughness of 19,37 nm had a thin InGaAsN film on a Si substrate obtained at the argon-nitrogen mixture pressure of 10 Pa -.


2021 ◽  
Vol 91 (10) ◽  
pp. 1538
Author(s):  
Л.И. Горай ◽  
Т.Н. Березовская ◽  
Д.В. Мохов ◽  
В.А. Шаров ◽  
К.Ю. Шубина ◽  
...  

Using direct laser lithography and liquid etching of polished vicinal Si(111) wafers, a technology was developed and diffraction gratings 500 /mm with a blaze angle of 4° were fabricated. The manufacturing process of a reflective Si-grating of a triangular profile (sawtooth) can be divided into four main steps: (1) obtaining a pattern of a protective mask for etching grooves; (2) anisotropic etching of grooves in KOH solution; (3) etching to smooth the grating profile and polish the surface of working facets; (4) coating to increase reflectivity. The samples obtained were characterized using scanning electron microscopy and atomic force microscopy methods to determine the shape of the groove profile and roughness: the shape turned out to be close to the ideal triangular, and the root-mean square roughness was less than 0.3 nm. With the help of the PCGrate™ code, taking into account the measured real groove profile, the diffraction efficiency of gratings operating in classical and conical mounts in soft-X-ray and extreme ultraviolet radiation has been simulated. The obtained efficiency values are close to the record ones for the corresponding spectral range and the Au-coating of the grating.


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