Effects of Grain Boundary on the Ferroelectric Properties of Selectively Grown PZT Thin Films

1999 ◽  
Vol 596 ◽  
Author(s):  
Jang-Sik Lee ◽  
Eung-Chul Park ◽  
Jung-Ho Park ◽  
Byung-Il Lee ◽  
Seung-Ki Joo
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Ferroelectric Properties ◽  
Electrical Performance ◽  
Breakdown Field ◽  
Pt Electrode ◽  
Pzt Thin Films ◽  
Growth Method ◽  
Fatigue Characteristics

AbstractThe effects of grain boundaries on the characteristics of the PZT thin films using single-grained PZT array by selective nucleation and growth method were investigated by locating the upper Pt electrode of 8 μm× 8 μm sized square directly on the single grains, 1 grain boundary and 4 grain boundaries in a controlled manner. It turned out that when there was no grain boundary, the best ferroelectric and electrical performance were obtained as expected. However, serious degradation was observed in polarization, leakage current, breakdown field and fatigue characteristics when grain boundary was contained in the area measured. This is the first qualitative investigation about the effects of the grain boundaries on the ferroelectric and electrical performance of the PZT thin films. It was found that degradation of the PZT thin films was accelerated with increasing the length of the grain boundaries within the top electrode and the main source of degradation in PZT thin films is grain boundary.

Characterization of Sputtered CdTe Thin Films with Electron Backscatter Diffraction and Correlation with Device Performance

2015 ◽  
Vol 21 (4) ◽  
pp. 927-935 ◽  
Author(s):  
Matthew M. Nowell ◽  
Michael A. Scarpulla ◽  
Naba R. Paudel ◽  
Kristopher A. Wieland ◽  
Alvin D. Compaan ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Electron Backscatter Diffraction ◽  
Electrical Performance ◽  
Poor Correlation ◽  
Twin Boundaries ◽  
Electron Backscatter ◽  
Backscatter Diffraction

AbstractThe performance of polycrystalline CdTe photovoltaic thin films is expected to depend on the grain boundary density and corresponding grain size of the film microstructure. However, the electrical performance of grain boundaries within these films is not well understood, and can be beneficial, harmful, or neutral in terms of film performance. Electron backscatter diffraction has been used to characterize the grain size, grain boundary structure, and crystallographic texture of sputtered CdTe at varying deposition pressures before and after CdCl2 treatment in order to correlate performance with microstructure. Weak fiber textures were observed in the as-deposited films, with (111) textures present at lower deposition pressures and (110) textures observed at higher deposition pressures. The CdCl2-treated samples exhibited significant grain recrystallization with a high fraction of twin boundaries. Good correlation of solar cell efficiency was observed with twin-corrected grain size while poor correlation was found if the twin boundaries were considered as grain boundaries in the grain size determination. This implies that the twin boundaries are neutral with respect to recombination and carrier transport.

A Study on the Selective Nucleations for Formation of Large Single Grains in PZT Thin Films

1999 ◽  
Vol 596 ◽  
Author(s):  
Jang-Sik Lee ◽  
Eung-Chul Park ◽  
Jung-Ho Park ◽  
Byung-Il Lee ◽  
Seung-Ki Joo
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Perovskite Phase ◽  
Breakdown Field ◽  
Pzt Thin Films ◽  
Random Nucleation ◽  
Saturation Polarization ◽  
Pt Electrodes ◽  
Pzt Films ◽  
Pt Films

AbstractSelective nucleation and lateral growing method have been developed for high quality ferroelectric PZT(65/35) thin films using perovskite-phase PZT island seed. The PZT films on PZT seed island were transformed into the perovskite phase at temperatures as low as 540°C, which is 150°C lower than compared to that of PZT thin films deposited on Pt films. The temperature difference enables lateral growth without undesirable random nucleation. Maximum grain sizes of the perovskite-phase PZT films were determined by the annealing temperature. The PZT thin films show a leakage current density of 8×10−8 A/cm2, breakdown field of 1240 kV/cm, saturation polarization of 42 μC/cm2, and remanent polarization of 30 μC/cm2, whose values were maintained up to 2×1011 cycles. In this study, we show that when there was no grain boundary in the area measured, degradation such as fatigue and retention was not observed even with Pt electrodes. So the main source of degradation is the grain boundary in the PZT thin films.

Issues in the Flexible Integration of Sputter-Deposited PZT Thin Films with Polysilicon and Ti/Pt Electrode Layers for Use as Sensors and Actuators in Microelectromechanical Systems (MEMS)

2000 ◽  
Vol 657 ◽  
Author(s):  
C.F. Knollenberg ◽  
T.D. Sands ◽  
A.S. Nickles ◽  
R.M. White
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Microelectromechanical Systems ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Pt Electrode ◽  
Electrode Layer ◽  
Pzt Thin Films ◽  
Pzt Films ◽  
Sputter Deposited

ABSTRACTSputter-deposited piezoelectric lead zirconate titanate (PZT) thin films with Ti/Pt and polysilicon electrode layers are being investigated for use in Microelectromechanical Systems (MEMS). Existing research shows the nucleation of the perovskite phase of the PZT is linked to the lattice spacing of the underlying Pt electrode and/or seed layers, and is key in obtaining PZT layers with good piezoelectric/ferroelectric properties. Our research with piezoelectric PZT films on Ti/Pt electrode layers aims at employing these films to generate and receive acoustic waves in flexural plate wave devices (FPWs). Our experiments indicate the formation of a random polycrystalline perovskite phase is linked to the emergence of oriented <100> Pt grains within the dominant <111>-oriented crystal structure during rapid thermal annealing in an oxygen environment. Pt films annealed in nitrogen, in contrast, retained their <111> preferential orientation without the formation of Pt <100> grains. PZT films deposited on these electrodes and annealed in nitrogen were strongly oriented in the <111> direction, but exhibited lossy ferroelectric behavior and were prone to delamination. We are also investigating the feasibility of using doped polysilicon electrode layers with PZT thin films. The multiple layers used with the Pt electrode (Pt, Ti, and SiO2 adhesion layer) have significant interactions with one another, and replacing these layers with a single electrode layer should alleviate these complications. A low-temperature PZT deposition process (300°C) and short annealing cycles (30 sec.), coupled with a TiO2 barrier/seed layer should prevent interdiffusion and reactions between the polysilicon and PZT layers. Our experiments show that PZT films deposited and annealed on doped polysilicon layers develop a random polycrystalline perovskite phase, but are subject to tensile cracking. The use of polysilicon as an electrode layer should also facilitate the integration of piezoelectric PZT layers with polysilicon surface micromachined structures using SiGe sacrificial layers.

The Effect of RuO2/Pt Hybrid Bottom Electrode Structure on The Microstructure and Ferroelectric Properties of Sol-Gel Derived PZT Thin Films

1997 ◽  
Vol 493 ◽  
Author(s):  
Seung-Hyun Kim ◽  
J. G. Hong ◽  
J. C. Gunter ◽  
H. Y. Lee ◽  
S. K. Streiffer ◽  
...  
Keyword(s):  
Thin Films ◽  
Leakage Current ◽  
Bottom Electrode ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Chemical Solution ◽  
Electrode Structure ◽  
Solution Deposition ◽  
Pzt Thin Films ◽  
Chemical Solution Deposition Method

ABSTRACTFerroelectric PZT thin films on thin RuO2 (10, 30, 50nm)/Pt hybrid bottom electrodes were successfully prepared by using a modified chemical solution deposition method. It was observed that the use of a lOnm RuO2Pt bottom electrode reduced leakage current, and gave more reliable capacitors with good microstructure compare to the use of thicker RuO2/Pt bottom electrodes. Typical P-E hysteresis behavior was observed even at an applied voltage of 3V, demonstrating greatly improved remanence and coercivity. Fatigue and breakdown characteristics, measured at 5V, showed stable behavior, and only below 13-15% degradation was observed up to 1010 cycles. Thicker RuO2 layers resulted in high leakage current density due to conducting lead ruthenate or PZT pyrochlore-ruthenate and a rosette-type microstructure.

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.

Post-Processing of Pulsed Laser-Deposited Pzt Thin Films

1991 ◽  
Vol 243 ◽  
Author(s):  
C. K. Chiang ◽  
W. Wong-Ng ◽  
L. P. Cook ◽  
P. K. Schenck ◽  
H. M. Lee ◽  
...  
Keyword(s):  
Thin Films ◽  
Amorphous Material ◽  
Ferroelectric Properties ◽  
Pulsed Laser ◽  
Linear Shrinkage ◽  
Laser Deposition ◽  
Amorphous Films ◽  
Pzt Thin Films ◽  
Si Substrates ◽  
Pzt Thin Film

AbstractPZT thin films were prepared by pulsed laser deposition on unheated Ptcoated Si substrates. As deposited, the films were amorphous. Films crystallized at 550 - 600 °C to produce predominantly crystalline ferroelectric PZT. Crystallization of the amorphous material was accompanied by a linear shrinkage of ∼2 %, as manifested in development of cracks in the film. Spacing, width and morphology of larger cracks followed a regular progression with decreasing film thickness. For film thicknesses less than 500 runm, much of the shrinkage was taken up by small, closely-spaced cracks of local extent. Implications for measurement of PZT thin film ferroelectric properties and processing are discussed.

Growth behavior and ferroelectric properties of Zr-rich PZT thin films deposited on various Pt electrodes

1999 ◽  
Vol 23 (1-4) ◽  
pp. 65-75 ◽  
Author(s):  
Suk-Kyoung Hong ◽  
Yong Eui Lee ◽  
J. Lee ◽  
Hyeong Joon Kim
Keyword(s):  
Thin Films ◽  
Ferroelectric Properties ◽  
Growth Behavior ◽  
Pzt Thin Films ◽  
Pt Electrodes
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