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.

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.

The physical and electrical characterizations of Cr-doped BiFeO3 ferroelectric thin films for nonvolatile memory applications

2015 ◽  
Vol 138 ◽  
pp. 86-90 ◽  
Author(s):  
Pi-Chun Juan ◽  
Jyh-Liang Wang ◽  
Tsang-Yen Hsieh ◽  
Cheng-Li Lin ◽  
Chia-Ming Yang ◽  
...  
Keyword(s):  
Thin Films ◽  
Nonvolatile Memory ◽  
Ferroelectric Thin Films ◽  
Memory Applications ◽  
Electrical Characterizations

Studies of Nanomechanical Properties of Pulsed Laser Deposited NbN films on Si Using Nanoindentation

2012 ◽  
Vol 1424 ◽  
Author(s):  
M. A. Mamun ◽  
A. H. Farha ◽  
Y. Ufuktepe ◽  
H. E. Elsayed-Ali ◽  
A. A. Elmustafa
Keyword(s):  
Thin Films ◽  
Pulsed Laser ◽  
Niobium Nitride ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
Force Microscopy ◽  
Atomic Force ◽  
Wide Range ◽  
Pile Up ◽  
Average Modulus

ABSTRACTNanomechanical and structural properties of pulsed laser deposited niobium nitride thin films were investigated using X-ray diffraction, atomic force microscopy, and nanoindentation. NbN film reveals cubic δ-NbN structure with the corresponding diffraction peaks from the (111), (200), and (220) planes. The NbN thin films depict highly granular structure, with a wide range of grain sizes that range from 15-40 nm with an average surface roughness of 6 nm. The average modulus of the film is 420±60 GPa, whereas for the substrate the average modulus is 180 GPa, which is considered higher than the average modulus for Si reported in the literature due to pile-up. The hardness of the film increases from an average of 12 GPa for deep indents (Si substrate) measured using XP CSM and load control (LC) modes to an average of 25 GPa measured using the DCM II head in CSM and LC modules. The average hardness of the Si substrate is 12 GPa.

Ferroelectric C-Axis Oriented Pb5Ge3O11 Thin Films for One Transistor Memory Application

1998 ◽  
Vol 541 ◽  
Author(s):  
Tingkai Li ◽  
Fengyan Zhang ◽  
Sheng Teng Hsu
Keyword(s):  
Thin Films ◽  
Ferroelectric Properties ◽  
Hysteresis Loops ◽  
Chemical Vapor ◽  
Dielectric Constants ◽  
Memory Devices ◽  
Leakage Currents ◽  
Fatigue Characteristics ◽  
Ferroelectric Memory ◽  
Memory Applications

AbstractOne transistor memory devices have been proposed recently. To meet the needs of one transistor memory applications, C-axis oriented Pb5Ge3O11 (PGO) thin films were prepared using metalorganic chemical vapor deposition (MOCVD) and rapid thermal processing (RTP). It was found that the nucleation of C-axis Pb5Ge3O11 phase started at a deposition temperature below 400°C and grain growth dominated at 500°C or above. With increasing annealing temperature, the remanent polarization (Pr) and coercive field (Ec) values increased, and the hysteresis loops of the Pb5Ge3O11 films were well saturated and symmetrical after the post-annealing. The C-axis PGO thin film showed good ferroelectric properties at 5V: 2Pr and 2Ec values were 2.0 - 4.0 µC/cm2 and 90 - 110 kV/cm, respectively. The films also showed excellent fatigue characteristics: no fatigue was observed up to 1 × 109 switching cycles. The retention and imprint properties have also been studied. The leakage currents of the PGO films were 2 - 5 × 10−7 A/cm2 at 100 kV/cm and dielectric constants were 40 - 70. The high quality MOCVD Pb5Ge3O11 films can be used for single transistor ferroelectric memory devices.

Sol-Gel derived Bi4-xNdxTi3O12 Thin Films and Their Characterization

2002 ◽  
Vol 737 ◽  
Author(s):  
R.E. Melgarejo ◽  
M.S. Tomar ◽  
A. Hidalgo ◽  
R.S. Katiyar
Keyword(s):  
Thin Films ◽  
Spin Coating ◽  
Bismuth Titanate ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complete Solid Solution ◽  
Sol Gel Process ◽  
Ferroelectric Memory ◽  
Initial Results

ABSTRACTNd substituted bismuth titanate Bi4-xNdxTi3O12 were synthesized by sol-gel process and thin films were deposited on Pt substrate (Pt/TiO2/SiO2/Si) by spin coating. Thin films, characterized by X-ray diffraction and Raman spectroscopy, shows complete solid solution up to the composition x < 1. Initial results indicate that the ferroelectric polarization increases with increasing Nd content in the film with 2Pr = 50μC/cm2 for x = 0.46, which may have application in non-volatile ferroelectric memory devices.

Long-term Room Temperature Instability in Thermal Conductivity of InGaZnO Thin Films

MRS Advances ◽  
2016 ◽  
Vol 1 (22) ◽  
pp. 1631-1636 ◽  
Author(s):  
Boya Cui ◽  
D. Bruce Buchholz ◽  
Li Zeng ◽  
Michael Bedzyk ◽  
Robert P. H. Chang ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Room Temperature ◽  
Storage Time ◽  
Laser Deposition ◽  
Low Oxygen ◽  
X Ray Diffraction ◽  
3Ω Method ◽  
X Ray

ABSTRACTThe cross-plane thermal conductivities of InGaZnO (IGZO) thin films in different morphologies were measured on three occasions within 19 months, using the 3ω method at room temperature 300 K. Amorphous (a-), semi-crystalline (semi-c-) and crystalline (c-) IGZO films were grown by pulsed laser deposition (PLD), followed by X-ray diffraction (XRD) for evaluation of film quality and crystallinity. Semi-c-IGZO shows the highest thermal conductivity, even higher than the most ordered crystal-like phase. After being stored in dry low-oxygen environment for months, a drastic decrease of semi-c-IGZO thermal conductivity was observed, while the thermal conductivity slightly reduced in c-IGZO and remained unchanged in a-IGZO. This change in thermal conductivity with storage time can be attributed to film structural relaxation and vacancy diffusion to grain boundaries.

Structural transformation of SbxSe100−x thin films for phase change nonvolatile memory applications

2005 ◽  
Vol 98 (1) ◽  
pp. 014904 ◽  
Author(s):  
M. J. Kang ◽  
S. Y. Choi ◽  
D. Wamwangi ◽  
K. Wang ◽  
C. Steimer ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Change ◽  
Structural Transformation ◽  
Nonvolatile Memory ◽  
Memory Applications

EFFECT OF GRAIN SIZE ON THE FERROELECTRIC PROPERTIES OF Bi3.25La0.75Ti3O12 Thin Films

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4469-4474 ◽  
Author(s):  
KYOUNG-TAE KIM ◽  
CHANG-IL KIM ◽  
DONG-HEE KANG ◽  
IL-WUN SHIM
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Remanent Polarization ◽  
Ferroelectric Properties ◽  
Fatigue Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Current Densities ◽  
Metalorganic Decomposition ◽  
Small Grains

The Bi 3.25 La 0.75 Ti 3 O 12 (BLT) thin films were prepared by metalorganic decomposition method. The effect of grain size on the ferroelectric properties during crystallization were investigated by x-ray diffraction and field emission scanning electron microscope. The grain size and the roughness of BLT films increase with increasing of drying temperature. The leakage current densities of the BLT thin film with large grains are higher than that with small grains. The remanent polarization of BLT increase with increasing grain size. As compared BLT with small grain size, the BLT film with larger grain size shows better fatigue properties. This may be explained that small grained films shows more degradation of switching charge than large grained films.

Preparation and CO2 Gas Sensitive Properties of CuO-SrTiO3-Based Semiconductor Thin Films

2007 ◽  
Vol 280-283 ◽  
pp. 311-314 ◽  
Author(s):  
Yan Fei Gu ◽  
Hui Ming Ji ◽  
Bin Zhang ◽  
Ting Xian Xu
Keyword(s):  
Thin Films ◽  
Chelating Agents ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Good Resistance ◽  
Gas Sensitivity ◽  
X Ray ◽  
Semiconductor Thin Films ◽  
Wide Range ◽  
Ft Ir

CuO-SrTiO3-based thin films were prepared by novel sol-gel technology on Al2O3 substrates using Cu(NO3)2, SrCl2 and TiCl4 as the starting materials, critic acid and ethylene glycol as chelating agents. CO2 sensing properties of the films were investigated. Structure characteristics of the sol and asgrown thin films were analyzed by FT-IR spectrum, X-ray diffraction and SEM. The results reveal that the films consisted of CuO phase and SrTiO3 phase have nanocrystalline microstructure at 750°C for 40 min. The modified CuO-SrTiO3 thin films exhibit good resistance-temperature and gas sensitivity properties in a wide range of temperature. The films exposed to 6% CO2 show that sensitivity are 32, and response and recover time are within 2 s at 250 °C operating temperature.

Effect of Composition on Ferroelectric Response of Bi4-xSmxTi3O12 Thin Films

2005 ◽  
Vol 902 ◽  
Author(s):  
Sandra Dussan ◽  
Maharaj Tomar ◽  
Ricardo Melgarejo ◽  
Ram Katiyar
Keyword(s):  
Thin Films ◽  
Solution Chemistry ◽  
Ferroelectric Polarization ◽  
Partial Substitution ◽  
X Ray Diffraction ◽  
Aurivillius Phase ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Trivalent Rare Earth ◽  
Ferroelectric Memory

AbstractBismuth titanate (Bi4Ti3O12) is an electroceramic within the Aurivillius phase material with week ferroelectric memory. However, the partial substitution of Bi ion by a trivalent rare earth resulted in improved ferroelectric polarization. We synthesized Bi4-xSmxTi3O12 by a solution chemistry route and thin films were deposited by spin coating on Pt (Pt/TiO2/SiO2/Si) substrate. X-ray diffraction studies of the films showed a stoichiometric solid solution for the composition x ≤0.85. The films showed fatigue free ferroelectric polarization (Pr = 19.8 µC/cm2) for the composition x = 0.70. The films showed low leakage current at room temperature, showing the possibility of lead free ferroelectric devices.

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