Simple Electrode-Barrier Structure Using Ir for Integration of PZT-Based High-Density Nonvolatile Memories

1998 ◽  
Vol 541 ◽  
Author(s):  
Kwang B. Lee ◽  
S. Tirumala ◽  
Y. Song ◽  
Sang O. Ryu ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Leakage Current ◽  
Electrical Contact ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Barrier Properties ◽  
Pzt Thin Films ◽  
Nonvolatile Memories ◽  
Si Wafer ◽  
Current Behavior

AbstractWe have investigated the electrode-barrier properties of Ir for PZT-based nonvolatile memories. Ir layer was rf-sputtered onto a poly-Si coated Si wafer. PZT thin films were deposited on Ir/poly-Si/SiO2/Si by means of sol-gel spin coating. Highly c-axis oriented perovskite PZT thin films were obtained, which might be due to the interface-controlled growth. We found that Ir in itself acted as an oxygen barrier, which was confirmed from the measurement of P-E hysteresis loops with the electrical contact between top-electrode and bottom-poly-Si. Remanent polarization and coercive field of 1rO2/PZT/Ir/poly-Si capacitor were 20 μC/cm2and 30 kV/cm, respectively and the capacitor showed negligible polarization fatigue up to 1011 switching repetitions. However, the leakage current density at the field of larger than 80 kV/cm was high, which was believed to be related to the unknown phase in PZT caused by the reaction of PbO with bottom-Ir. Such high leakage current behavior could be successively improved by the insertion of vacuum-annealed IrOx buffer layer between PZT/Ir. The electrical properties of IrOx/PZT/annealed-IrO2Ir/poly-Si capacitors are also discussed.

Preparation and Electrical Characteristics of (100), (111), and Randomly Oriented PZT Thin Films

1994 ◽  
Vol 361 ◽  
Author(s):  
Chang Jung Kim ◽  
Dae Sung Yoon ◽  
Joon Sung Lee ◽  
Chaun Gi Choi ◽  
Won Jong Lee ◽  
...  
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Test System ◽  
Electrical Characteristics ◽  
Pzt Thin Films ◽  
Pole Figures ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Drying Conditions

ABSTRACTThe (100), (111) and randomly oriented PZT thin films were fabricated on Pt/Ti/Coming 7059 glass using sol-gel method. The thin films having different orientation were fabricated by different drying conditions for pyrolysis. The preferred orientations of the PZT thin films were observed using XRD, rocking curves, and pole figures. The microstructures were investigated using SEM. The hysteresis loops and capacitance-voltage characteristics of the films were investigated using a standardized ferroelectric test system. The dielectric constant and current-voltage characteristics of the films were investigated using an impedance analyzer and pA meter, respectively. The films oriented in a particular direction showed superior electrical characteristics to the randomly oriented films.

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.

EFFECT OF PRE-HEATING TEMPERATURE ON THE CHARACTERISTICS OF PZT THIN FILMS GROWN BY USING A TRIOL SOL–GEL ROUTE

2007 ◽  
Vol 14 (02) ◽  
pp. 229-234
Author(s):  
SARAWUT THOUNTOM ◽  
MANOCH NAKSATA ◽  
KENNETH MACKENZIE ◽  
TAWEE TUNKASIRI
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Heating Temperature ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Lead Zirconate ◽  
Pzt Thin Films ◽  
Pzt Films ◽  
Ferroelectric Hysteresis

Lead zirconate titanate (PZT) films with compositions near the morphotropic phase boundary were fabricated on Pt (111)/ Ti / SiO 2/ Si (100) using the triol sol–gel method. The effect of the pre-heating temperature on the phase transformations, microstructures, electrical properties, and ferroelectric properties of the PZT thin films was investigated. Randomly oriented PZT thin films pre-heated at 400°C for 10 min and annealed at 600°C for 30 min showed well-defined ferroelectric hysteresis loops with a remnant polarization of 26.57 μC/cm2 and a coercive field of 115.42 kV/cm. The dielectric constant and dielectric loss of the PZT films were 621 and 0.0395, respectively. The microstructures of the thin films are dense, crack-free, and homogeneous with fine grains about 15–20 nm in size.

STRUCTURAL AND FERROELECTRIC CHARACTERIZATION OF PZT THIN FILMS

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4460-4464 ◽  
Author(s):  
YING YANG ◽  
ZHIMING CHEN ◽  
GAOYANG ZHAO ◽  
WEIHUA ZHANG
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Relative Dielectric Constant ◽  
Dissipation Factor ◽  
Dip Coating ◽  
Test System ◽  
Pzt Thin Films ◽  
Different Temperatures ◽  
Lcr Meter

Pb(Zr x Ti 1-x ) O 3 (PZT) films were prepared on the ITO coated glass plates in sol-gel dip-coating process and post-annealing at different temperatures. The structural properties of the films were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It is shown that the PZT ferroelectric thin films with (110) preferential orientation and well-crystallized perovskite structure can be obtained after annealing at 680°C for 30 minutes. The P-E hysteresis loops were measured by the Sawyer-Tower test system with a compensation resistor at room temperature. Values of the remanent polarization (Pr) and the coercive electric field (Ec) are 19.36• C/cm 2 and 95 kV/cm, respectively, for the prepared PZT thin films. The relative dielectric constant εr and the dissipation factor tg• of the PZT thin films are equal to 639 and 0.23, respectively, which were measured in a LCR meter.

Structure and Electrical Properties of Rapid Thermally Annealed PZT Films Deposited through Sol-Gel Process

2007 ◽  
Vol 336-338 ◽  
pp. 39-41
Author(s):  
Liang Sheng Qiang ◽  
Dong Yan Tang ◽  
Mu Han
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Molar Ratio ◽  
Hot Plate ◽  
Pzt Thin Films ◽  
Good Surface ◽  
Sol Gel Process ◽  
Pzt Films ◽  
High Fatigue

In present work, sol-gel process is used to direct the organization of high quality and pore-free parasite PZT thin films with a composition near the morphotropic phase boundary (Zr/Ti = 52/48). The PZT transparent sol can be obtained by dissolving the zirconium oxynitrate, butyl titanate and lead acetate in ethylene glycol with the molar ratio of 0.52:0.48:1 and the PZT gel can be gained by spin-coating. In such process, PZT thin films can be readily prepared by hydrolysis on hot plate at 350°C for 20min and annealing in RTA at 650°C for 1 minute. The structural and electric characteristics of the films have been carried out by XRD, AFM and the C-V measurements, etc. Experimental results have indicated that by treating film RTA at 6508 for 1 minute film with perfect crystallization and good surface morphology with a RMS roughness of 2.0nm can be obtained, and the remnant polarization Pr (28.5 μC/cm2) and coercive field Ec (39.8kV/cm) are obtained in the P-E hysteresis loops. The films have a dielectric constant ε of 1080 and a dielectric loss tanδ of 0.01 at 1 kHz. Ferroelectric polarization fatigue test of the films has shown that high fatigue resistance up to 3 × 1010 cycles before Pr is decreased by 50%.

Sol-gel doped-PZT thin films for integrated tunable capacitors

2015 ◽  
Vol 2015 (1) ◽  
pp. 000256-000261 ◽  
Author(s):  
Warda Benhadjala ◽  
Gwenael Le Rhun ◽  
Christel Dieppedale ◽  
Florence Sonnerat ◽  
Jennifer Guillaume ◽  
...  
Keyword(s):  
Thin Films ◽  
Leakage Current ◽  
Breakdown Voltage ◽  
Piezoelectric Materials ◽  
Sol Gel ◽  
Wafer Level ◽  
Pzt Thin Films ◽  
Tunable Capacitors ◽  
Metal Insulator Metal ◽  
Dc Bias

Integrated metal-insulator-metal (MIM) capacitors using sol-gel PZT doped with lanthanum (La, PLZT), manganese (Mn, PMZT) and niobium (Nb, PNZT) were successfully processed and characterized for tunable applications. Dielectric properties of doped-PZT were investigated and compared to those of pure PZT. Wafer-level measurements were conducted with a particular attention on tunability evaluation under DC bias voltage. Tunability, leakage current density and breakdown voltage of pure PZT thin films were 77.6% (i.e. 4.5:1) at 10kHz/10V, 4.8.10−5 A/cm2 at 870kV and 37.5V (i.e. 1.63 MV/cm) respectively. The breakdown voltage increased by 25% with La doping and by 50% with Nb and Mn. The lowest leakage current were achieved by PNZT (7.0.10−7 A/cm2 at 870kV) while PMZT films exhibited an outstanding tunability reaching 88.8% (i.e. 8.9:1) at 100 kHz and 20V. Enhanced performances of the developed doped-PZT were compared to the state of the art. Results indicate that electrical properties of sol-gel doped-PZT achieved those of conventionally deposited materials. It is noteworthy that obtained PMZT tunability is among the highest ones reported in the literature for PZT-derived thin films but also for other piezoelectric materials.

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