Basic Thin Film Process for Perovskite Ferroelectric Materials

1990 ◽  
Vol 200 ◽  
Author(s):  
Hideaki Adachi ◽  
Kiyotaka Wasa

ABSTRACTThin film process for ferroelectric perovskite oxides has been investigated. Amorphous, polycrystal, and epitaxial thin films of Pb-based perovskite ferroelectrics were prepared by rf-magnetron sputtering, and their properties were discussed. Epitaxial PLZT thin films showed similar dielectric properties as PLZT bulk ceramics and also showed strong electrooptic effect. For further investigation, film preparation process was developed by multitarget sputtering and quaternary PLZT thin film with excellent epitaxial crystallinity was realized by using a graded composition layer.

1991 ◽  
Vol 243 ◽  
Author(s):  
Shigenori Hayashi ◽  
Kenji Iijima ◽  
Takashi Hirao

AbstractThin film process for Pb-based perovskite ferroelectrics has been investigated. Synthesis of epitaxial PLZT, PLT and PZT thin films by rfmagnetron sputtering in our laboratory was reviewed. Basic thin film process and applications were discussed. For further investigation, film preparation process was developed by co-deposition and assisted deposition techniques. The substrate temperature required for in-situ preparation of perovskite could be reduced to room temperature by an ion- and photoassisted co-evaporation technique.


1994 ◽  
Vol 9 (11) ◽  
pp. 2959-2967 ◽  
Author(s):  
Kiyotaka Wasa ◽  
Toshifumi Satoh ◽  
Kenji Tabata ◽  
Hideaki Adachi ◽  
Yasumufi Yabuuchi ◽  
...  

The microstructures of sputtered thin films of lead-lanthanum zirconate-titanate (PLZT) on (0001) sapphire substrate have been studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Thin films of polycrystalline PLZT (9/65/35), Pb0.91La0.09Zr0.65Ti0.35O3, were prepared on a (0001) sapphire substrate by reactive sputtering, using the dc-magnetron system with a multitarget, Pb, La, Zr, and Ti at the substrate temperature of 700 °C. The PLZT thin films comprised (111) oriented small crystallites of PLZT. Although the average direction of the crystal orientation corresponded to the ideal epitaxial relationship (111) PLZT ‖ (0001) sapphire, the individual crystallites showed misalignment in both the growth direction and the film plane. The thin films could not be considered epitaxially grown films. From analysis of the TEM images, there exists an interfacial region between the PLZT thin film and the substrate. The interfacial region comprises ordered clusters of (111), disordered (101), and/or (110) PLZT crystallites. The presence of the interfacial region will suppress ideal epitaxial growth with uniform crystal orientation. It is confirmed that the addition of the buffer layer of graded composition of PLT-PLZT, between the substrate and the PLZT thin film, will suppress the formation of the disordered interfacial region and will enhance the epitaxial growth of the (111) PLZT on (0001) sapphire with three-dimensional crystal orientations.


2000 ◽  
Vol 655 ◽  
Author(s):  
Fan Chu ◽  
Glen Fox ◽  
Tom Davenport

AbstractThe requirements for future ferroelectric non-volatile memories (FRAM) include lower operating voltages, higher densities and tighter design rules. In order to achieve these requirements the key component of the FRAM device, viz., the PbZrxTi1划xO3 (PZT) thin film capacitor must be scaled dimensionally to obtain reduced film thickness and capacitor area. This paper presents the ferroelectric performance of RF magnetron sputtered PLZT thin films with thickness scaled down to 1000Å. The switching performance of the thickness scaled PLZT thin films meets the requirements of 1.8V FRAM device. Though PLZT ceramic thin films, of which the fatigue is often a concern, are utilized as non-volatile component, excellent fatigue performance was observed. The scaled PLZT thin film capacitors are fatigue free up to 1011 fatigue cycles (E=200kV/cm). The scaled 1000Å PLZT thin films also showed good imprint performance. The opposite-state charge after 10 years baking at 150°C was still above the sensing level. The thickness scaled PZT thin films, showing dramatically improved ferroelectric performance, can be applied to the manufacturing of low voltage FRAM products.


2020 ◽  
Vol 233 ◽  
pp. 05005
Author(s):  
P. Machado ◽  
F.G. Figueiras ◽  
R. Vilarinho ◽  
J.R.A. Fernandes ◽  
P.B. Tavares ◽  
...  

GdMnO3 epitaxial thin films were deposited onto (110)-oriented SrTiO3 substrates by RF magnetron sputtering. The structure, microstructure, dielectric and magnetic properties were investigated in detail. The XRD results revealed that the GdMnO3 thin films exhibit an epitaxial strained orthorhombic symmetry and grow preferably in off-plane (001) orientation, wherein the basal lattice parameters are strained by the substrate lattice. A dielectric relaxation process was ascertained, whose activation energy is sensitive to the magnetic phase transitions, occurring at 41 K and at 20 K, respectively. The canted nature of the low temperature magnetic phase is discussed.


1996 ◽  
Vol 433 ◽  
Author(s):  
Bo Jiang ◽  
Venkatasubramani Balu ◽  
Tung-Sheng Chen ◽  
Shao-Hong Kuah ◽  
Jack C. Lee

AbstractPolarization relaxation in PZT and PLZT (with La concentration from 0% to 10%) thin film capacitors was characterized in the time range from 10 ns to 1000 s. It was found that at zero volt the polarization in PZT and PLZT thin films changes logarithmically with time, P(t) = blog(t) + P0, and the polarization current density J(t) = dP(t)/ dt obeys the Curie-von Schweidler Law, J(t) = b. t−x, with n = 1 from 100 ns extending to 10 s. Over 10 s, the exponent n in the J-t relationship becomes less than 1. The coefficient b in the Q-t and J-t relationship at zero volt correlates strongly with the remanent polarization. La doping in PZT reduces remanent polarization and reduces relaxation.


2020 ◽  
Vol 102 (21) ◽  
Author(s):  
Stephan Geprägs ◽  
Björn Erik Skovdal ◽  
Monika Scheufele ◽  
Matthias Opel ◽  
Didier Wermeille ◽  
...  

2013 ◽  
Vol 27 (22) ◽  
pp. 1350156 ◽  
Author(s):  
R. J. ZHU ◽  
Y. REN ◽  
L. Q. GENG ◽  
T. CHEN ◽  
L. X. LI ◽  
...  

Amorphous V 2 O 5, LiPON and Li 2 Mn 2 O 4 thin films were fabricated by RF magnetron sputtering methods and the morphology of thin films were characterized by scanning electron microscopy. Then with these three materials deposited as the anode, solid electrolyte, cathode, and vanadium as current collector, a rocking-chair type of all-solid-state thin-film-type Lithium-ion rechargeable battery was prepared by using the same sputtering parameters on stainless steel substrates. Electrochemical studies show that the thin film battery has a good charge–discharge characteristic in the voltage range of 0.3–3.5 V, and after 30 cycles the cell performance turned to become stabilized with the charge capacity of 9 μAh/cm2, and capacity loss of single-cycle of about 0.2%. At the same time, due to electronic conductivity of the electrolyte film, self-discharge may exist, resulting in approximately 96.6% Coulombic efficiency.


2018 ◽  
Vol 53 ◽  
pp. 01008
Author(s):  
Feihu Tan ◽  
XiaoPing Liang ◽  
Feng Wei ◽  
Jun Du

The amorphous LiPON thin film was obtained by using the crystalline Li3PO4 target and the RF magnetron sputtering method at a N2 working pressure of 1 Pa. and then the morphology and composition of LiPON thin films are analysed by SEM and EDS. SEM shows that the film was compact and smooth, while EDS shows that the content of N in LiPON thin film was about 17.47%. The electrochemical properties of Pt/LiPON/Pt were analysed by EIS, and the ionic conductivity of LiPON thin films was 3.8×10-7 S/cm. By using the hard mask in the magnetron sputtering process, the all-solid-state thin film battery with Si/Ti/Pt/LiCoO2/LiPON/Li4Ti5O12/Pt structure was prepared, and its electrical properties were studied. As for this thin film battery, the open circuit voltage was 1.9 V and the first discharge specific capacity was 34.7 μAh/cm2·μm at a current density of 5 μA/cm-2, indicating that is promising in all-solidstate thin film batteries.


2011 ◽  
Vol 1288 ◽  
Author(s):  
Rashmi Menon ◽  
K. Sreenivas ◽  
Vinay Gupta

ABSTRACTZinc Oxide (ZnO), II-VI compound semiconductor, is a promising material for ultraviolet (UV) photon sensor applications due to its attractive properties such as good photoconductivity, ease processing at low temperatures and excellent radiation hardness. The rf magnetron sputtering is a suitable deposition technique due to better control over stoichiometry and deposition of uniform film. Studies have shown that the presence of surface defects in ZnO and subsequently their passivation are crucial for enhanced photo-response characteristics, and to obtain the fast response speed. Worldwide efforts are continuing to develop good quality ZnO thin films with novel design structures for realization of an efficient UV photon sensor. In the present work, UV photon sensor is fabricated using a ZnO thin films deposited by rf magnetron sputtering on the corning glass substrate. Photo-response, (Ion/Ioff) of as-grown ZnO film of thickness 100 nm is found to be 3×103 with response time of 90 ms for UV intensity of 140 μW/cm2 (λ = 365 nm). With irradiation on ZnO thin film by pulsed Nd:YAG laser (forth harmonics 266 nm), the sensitivity of the UV sensor is found to enhance. The photo-response increases after laser irradiation to 4x104 with a fast response speed of 35 ms and attributed to the change in surface states and the native defects in the ZnO thin film. Further, enhancement in the ultraviolet (UV) photo-response (8×104) of detector was observed after integrating the nano-scale islands of Sn metal on the surface of laser irradiated ZnO thin film.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Gyu-bong Cho ◽  
Tae-hoon Kwon ◽  
Tae-hyun Nam ◽  
Sun-chul Huh ◽  
Byeong-keun Choi ◽  
...  

LiNiO2thin films were fabricated by RF magnetron sputtering. The microstructure of the films was determined by X-ray diffraction and field-emission scanning electron microscopy. The electrochemical properties were investigated with a battery cycler using coin-type half-cells. The LiNiO2thin films annealed below 500°C had the surface carbonate. The results suggest that surface carbonate interrupted the Li intercalation and deintercalation during charge/discharge. Although the annealing process enhanced the crystallization of LiNiO2, the capacity did not increase. When the annealing temperature was increased to 600°C, the FeCrNiO4oxide phase was generated and the discharge capacity decreased due to an oxygen deficiency in the LiNiO2thin film. The ZrO2-coated LiNiO2thin film provided an improved discharge capacity compared to bare LiNiO2thin film suggesting that the improved electrochemical characteristic may be attributed to the inhibition of surface carbonate by ZrO2coating layer.


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