Effect of Annealing Treatment on PZT Thin Fiilm Properties Using Oxygen 18 Depth Profiling Technique

1998 ◽  
Vol 541 ◽  
Author(s):  
F. Ayguavives ◽  
B. Ea-Kim ◽  
B. Agius ◽  
I. Vickridge ◽  
A. I. Kingon

AbstractLead zirconate titanate (PZT) thin films have been deposited in a reactive argon/oxygen gas mixture from a metallic target of nominal composition Pb1.1(Zr0.4Ti0.6)O3 by rf magnetron sputtering on Si substrates and RuO2/SiO2/Si structures. During plasma deposition, in situ Optical Emission Spectroscopy (OES) measurements clearly show a correlation between the evolution of characteristic atomic emission line intensities and the thin film composition determined by simultaneous Rutherford Backscattering Spectroscopy (RBS) and Nuclear Reaction Analysis (NRA). As a result, the cathode surface state can be monitored by OES to ensure a good compositional transferability from the target to the film and reproducibility of thin film properties for given values of deposition parameters. Electrical properties and crystallization have been optimized with a 90 nm PZT thin film grown on RuO2 electrodes. These PZT films, annealed with a very modest thermal budget (550°C) are fatigue-free and show very low leakage currents (J=2.10−8 A/cm2 at 1 V). The use of a metallic target allows us to control the oxygen incorporation in the PZT thin film and also, using 18O as a tracer, to study the oxygen vacancy migration which plays a key role in fatigue, leakage current, and electrical degradation/breakdown in PZT thin films.

1994 ◽  
Vol 361 ◽  
Author(s):  
B. Ea Kim ◽  
M.C. Hugon ◽  
F. Varniere ◽  
B. Agius ◽  
H. Achard ◽  
...  

ABSTRACTDue to their high dielectric constant, good chemical stability and good insulating properties, lead zirconate titanate (PZT) thin films are considered as promising materials to replace Si3N4 and Ta2O5 for use as the capacitor dielectric in future high density DRAMs. Moreover, the ferroelectric quality of PZT films also allows use of this material in non volatile memories. In this paper, we investigate the properties of PZT films deposited from an oxide target of nominal composition {Pb1.1(Zr0.55,Ti0.45)O3} in a radio frequency (rf) magnetron sputtering system. The Pt(deposited at 450°C)/[TiN/Ti/BPSG/Si] structure annealed at 450°C at 10−6 mbar (Pt(450°C)/{TiN/Ti/BPSG/Si}450°c,10–6mbar) was used as a substrate material in this work. The PZT films were deposited at different pressures, and different substrate temperatures ranging from floating temperature to 400°C; the thicknesses of the sputtered films were in the 15–720 nm range. The kinetics of the sputtering process and the effect of sputtering parameters on film composition have been studied and related to the continuously monitored optical emission of the plasma. The relative cation and oxygen compositions of the films were determined by a new method based on the simultaneous use of Rutherford Backscattering Spectrometry (RBS) and Nuclear Reaction Analysis (NRA) induced by a deuteron beam. The conditions for the deposition of stoichiometric PZT thin films were established.Electrical characterizations of the PZT films including resistivity, dielectric constant, dissipation factor were studied as a function of the temperature. From initial electrical measurements, it appears that a dielectric constant of 740 can be obtained for PZT 55/45 films deposited on a previously annealed Pt/TiN/Ti/BPSG/Si structure.


2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Qing Guo ◽  
G. Z. Cao ◽  
I. Y. Shen

Lead zirconate titanate (PbZrxTi1-xO3, or PZT) is a piezoelectric material widely used as sensors and actuators. For microactuators, PZT often appears in the form of thin films to maintain proper aspect ratios. One major challenge encountered is accurate measurement of piezoelectric coefficients of PZT thin films. In this paper, we present a simple, low-cost, and effective method to measure piezoelectric coefficient d33 of PZT thin films through use of basic principles in mechanics of vibration. A small impact hammer with a tiny tip acts perpendicularly to the PZT thin-film surface to generate an impulsive force. In the meantime, a load cell at the hammer tip measures the impulsive force and a charge amplifier measures the responding charge of the PZT thin film. Then the piezoelectric coefficient d33 is obtained from the measured force and charge based on piezoelectricity and a finite element modeling. We also conduct a thorough parametric study to understand the sensitivity of this method on various parameters, such as substrate material, boundary conditions, specimen size, specimen thickness, thickness ratio, and PZT thin-film material. Two rounds of experiments are conducted to demonstrate the feasibility and accuracy of this new method. The first experiment is to measure d33 of a PZT disk resonator whose d33 is known. Experimental results show that d33 measured via this method is as accurate as that from the manufacturer's specifications within its tolerance. The second experiment is to measure d33 of PZT thin films deposited on silicon substrates. With the measured d33, we predict the displacement of PZT thin-film membrane microactuators. In the meantime, the actuator displacement is measured via a laser Doppler vibrometer. The predicted and measured displacements agree very well validating the accuracy of this new method.


1999 ◽  
Vol 596 ◽  
Author(s):  
Tingkai Li ◽  
Sheng Teng Hsu ◽  
Yufei Gao ◽  
Mark Engelhard

AbstractThree kinds of oriented electrodes of Pt, Ir and Pt/Ir electrodes were prepared using electron beam evaporation techniques for deposition of PZT thin films. An oxide MOCVD reactor with liquid delivery system was used for the growth of PZT thin films. [Pb(thd)2], Zr(TMHD)4 and Ti(IPO)4 were dissolved in a mixed solvent of tetrahydrofuran or butyl ether, isopropanol and tetraglyme to form a precursor source. The deposition temperature and pressure were 500 - 650°C and 5 - 10 Torr, respectively. The experimental results showed PZT thin film deposited on various electrodes had different phase formation, microstructure and ferroelectric property. The X-ray patterns showed the perovskite phase of PZT was formed on both Ir and Pt/Ir electrodes at 550°C. The grain size of the PZT thin film increases after a further, higher temperature annealing. The as-deposited PZT thin film on Pt electrode exhibits pyrochlore phase at 550°C. The phase is transformed to perovskite phase after 650°C annealing. The experimental results also indicated that the MOCVD PZT thin film on Pt/Ir exhibits better ferroelectric and electrical properties compared to those deposited on Pt and Ir electrodes. A 300 nm thick PZT thin film on Pt/Ir electrode has a square, well saturated, and symmetrical hysteresis loop with 2Pr value of 40 μC/cm2 and 2Ec of 73 kV/cm at an applied voltage of 5 V. The hysteresis loop of the PZT thin film is almost saturated at 2 V. The leakage current of the film is 6.16 × 10−7 A/cm2 at 100 KV/cm. The electrode effects on ferroelectric properties of PZT thin films also have been investigated.


2013 ◽  
Vol 302 ◽  
pp. 8-13
Author(s):  
Shun Fa Hwang ◽  
Wen Bin Li

PZT thin film was fabricated by using RF-sputtering process, and platinum was used as bottom electrodes. The sputtering gases were Ar:O2=25:0 sccm, Ar:O2=20:5 sccm, or Ar:O2=15:10 sccm. After sputtering, the PZT film was annealed for 5 minutes under O2 gas environment and at the temperature of 600 0C, 650 0C, 700 0C or 750 0C. To judge the quality of the deposited PZT film, its physical properties and electric properties were evaluated. The results indicate that the best crystallization temperature of PZT thin film is about 700 0C. Also, the roughness of the PZT thin film becomes larger with the increasing of annealing temperature. By adding more oxygen in the sputtering gas, one could have better crystallization of the PZT film. As for the electrical properties, the leakage current of PZT thin film increases with the increasing of annealing temperature. Furthermore, the ferroelectric property is affected by the crystallization amount of perovskite, the thickness of PZT thin film, and the diffusion situation between the bottom electrode and the PZT film.


1990 ◽  
Vol 200 ◽  
Author(s):  
D. J. Johnson ◽  
D. T. Amm ◽  
E. Griswold ◽  
K. Sreenivas ◽  
G. Yi ◽  
...  

ABSTRACTSmall signal dielectric response is reported for a variety of PZT thin film samples. Small and large signal responses, recorded simultaneously during the fatiguing of PZT thin films, are used to identify distinct fatigue mechanisms. Microcracking or electrode delamination less than 100 Å is sufficient to explain the high correlation between the dielectric permittivity and remanent polarization during fatigue.


2020 ◽  
Vol 10 (04) ◽  
pp. 2050010
Author(s):  
M. Kathiresan ◽  
Jain Jose ◽  
E. Varadarajan ◽  
R. Ramesh ◽  
V. Natarajan ◽  
...  

Doped lead–zirconate–titanate (PZT) thin films are preferred for the development of micro–electro–mechanical systems (MEMS)-based acoustic sensors because of their inherent higher dielectric and piezoelectric coefficients. Patterning process is used to develop such MEMS devices which is highly complex even for undoped PZT thin films; therefore, the problem is further cumbersome for doped PZT thin films due to the presence of added dopant elements and their associated chemistry. This paper presents patterning of strontium (Sr) and lanthanum (La) co-doped PZT thin film (PSLZT) deposited on platinized silicon substrate using wet and dry etching processes for fabricating a diaphragm structure with thickness of 15–25[Formula: see text][Formula: see text]m and diameter of 1.4–2[Formula: see text]mm, suitable for acoustic sensing applications. The effects of various etching conditions have been studied and the results are reported. It is found that the dry etching is the most suited process for realizing the piezoelectric MEMS structure due to its higher etching resolution. An appreciable etching rate of 260–270[Formula: see text]nm/min with smooth vertical sidewalls is achieved. The silicon diaphragm with patterned PSLZT thin film is found to retain more than 80% of its dielectric and piezoelectric coefficients and has a resonance of 1.43[Formula: see text]MHz.


1991 ◽  
Vol 243 ◽  
Author(s):  
E. Catitan ◽  
B. Agius ◽  
H. Achard ◽  
J.P. Joly ◽  
J.C. Cheang Wong ◽  
...  

AbstractLead zirconate titanate thin films have been grown by rf magnetron sputtering an oxide target of nominal composition [Pb(Zr0.55,Ti0.45)O3 or PZT] in argon. The kinetics of the sputtering process and the effect of sputtering parameters on film composition have been studied and related to the continuously monitored optical emission of the plasma. The relative and absolute cation and oxygen compositions of the thin films were determined by a new method based on the simultaneous use of Rutherford backscattering spectroscopy (RBS) and nuclear reaction analysis (NRA) induced by a deuteron beam. The conditions for the deposition at room temperature of stoichiometric PZT films were established.


Author(s):  
Norio Tagawa ◽  
Ken-ichi Kitamura ◽  
Atsunobu Mori

This paper describes the development of novel PZT thin films for active sliders in hard disk drives. So far, it is common that single-layered thin films are used as micro-actuators for conventional PZT thin films such as sol-gel or sputtered thin films. In this study, however, the novel composite PZT thin films are developed. The feature is that sol-gel PZT thin film is deposited on sputtered PZT thin film fabricated on Pt/Ti bottom electrode. These multilayered composite PZT thin films are found to have the higher (111) preferred orientation as well as better P-E hysteresis loop characteristics than not only sol-gel PZT thin films but also sputtered PZT thin films. Furthermore, the piezoelectric strain constant d31 for the novel PZT thin films is identified to be 189 × 10−12m/V. This value is 2.0 times higher than that for conventional PZT thin films and it is found that the novel PZT thin films have good piezoelectric properties.


1999 ◽  
Vol 596 ◽  
Author(s):  
Chang Jung Kim ◽  
Ilsub Chung

AbstractLanthanum doped lead zirconate titanate (PZT) thin films have been prepared on Pt/IrO2/Ir/SiO2/Si substrates to improve the ferroelectric and retention properties. The microstructure and electrical properties of the PZT capacitors were evaluated as a function of La content. The crystalline orientation was appreciably influenced by the addition of La in PZT thin films. The microstructures of films containing 0 and 0.5 mol% La were single phase perovskite, but for La = 1 mol%, a second phase was detected by SEM observation. The 0.5 mol% La doped PZT thin film capacitor showed the best ferroelectric and retention properties for ferroelectric random access memory compared to non-doped PZT.


2011 ◽  
Vol 1299 ◽  
Author(s):  
L.M. Sanchez ◽  
D.M. Potrepka ◽  
G.R. Fox ◽  
I. Takeuchi ◽  
R.G. Polcawich

ABSTRACTLeveraging past research activities in orientation control of lead zirconate titanate (PZT) thin films [1,2], this work attempts to optimize those research results using the fabrication equipment at the U.S. Army Research Laboratory so as to achieve a high degree of {001}- texture and improved piezoelectric properties. Initial experiments examined the influence of Ti/Pt and TiO2/Pt thins films used as the base-electrode for chemical solution deposition PZT thin film growth. In all cases, the starting silicon substrates used a 500 nm thermally grown silicon dioxide. The Pt films were sputter deposited onto highly textured titanium dioxide films grown by a thermal oxidation process of a sputtered Ti film [3]. The second objective targeted was to achieve highly {001}-textured PZT using a seed layer of PbTiO3 (PT). A comparative study was performed between Ti/Pt and TiO2/Pt bottom electrodes. The results indicate that the use of a highly oriented TiO2 led to highly {111}-textured Pt, which in turn improved both the PT and PZT orientations. Both PZT (52/48) and (45/55) thin films with and without PT seed layers were deposited and examined via x-ray diffraction methods (XRD) as a function of annealing temperature. As expected, the PT seed layer provides significant improvement in the PZT {001}-texture while suppressing the {111}-texture of the PZT. Improvements in the Lotgering factor (f) were observed upon comparison of the original Ti/Pt/PZT process (f=0.66) with samples using the PT seed layer as a template, Ti/Pt/PT/PZT (f=0.87), and with films deposited onto the improved Pt electrodes, TiO2/Pt/PT/PZT (f=0.96).


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