• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.3
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• pp.205-212
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• 2002

The growth characteristics of metal-organic chemical vapor deposition (MOCVD) $Pb(Zr_xTi_{1-x})O_3 (PZT) thin films were investigated for the application of high-density ferroelectric random access memories (FRAM) devices beyond 64Mbit density. The supply control of Pb precursor plays the most critical role in order to achieve a reliable process for PZT thin film deposition. We have monitored the changes in the microstructure and electrical properties of films on increasing the Pb precursor supply into the reaction chamber. Under optimized conditions, $Ir/IrO_2/PZT(100nm)/Ir capacitor shows well-saturated hysteresis loops with a remanent polarization (Pr) of $~28{\mu}C/textrm{cm}^2$ and coercive voltage of 0.8V at 2.5V. Other issues such as step coverage, compositional uniformity and low temperature deposition was discussed in viewpoint of actual device application.

• Journal of the Korean institute of surface engineering
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• v.29 no.5
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• pp.330-337
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• 1996

A rf reactive sputter deposition technique was adopted to deposit ferroelectric lead zirconate titanate (PZT) thin films with high rate from a ZrTi alloy target combined with PbO pellets. Deposition characterisitics including the effects of PbO are ratio were discussed. A new deposition mode called the quasi-metallic mode was observed. Perovskite PZT films were prepared at a growth temperature as low as$ 450^{\circ}C$. However, because the target structure is unstable, weproposed a mixture target consisted of Zr, Ti and PbO. Fundamental experiments were investigated using the powder target. Perovskite PZT film could be obtained at $450^{\circ}C$ with better electrical properties also.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.105-105
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• 1994

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.3
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• pp.105-108
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• 2008

Four different thin films were made by depositing PZ and PT in different stacking sequences. PZ and PT phases are preferably co-existed in sample A and C that are annealing after each coatings. The sample B and D, on the other hands, have tendency toward the PZT phase after co-firing the sample. The sample B that started from PT stacking first was more stable PZT phase than that of PZ first sample D.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.3
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• pp.188-192
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• 2000

In this study PZT etching was performed using planar inductively coupled Ar/Cl$_2$/BCI$_3$ plasma. The etch rate of PZT film was 2450 $\AA$/min at Ar(20)/BCl$_3$(80) gas mixing ratio and substrate temperature of 8$0^{\circ}C$. X-ray photoelectron spectroscopy(XPS) analysis for films composition of etched PZT surface was utilized. The chemical bond of PbO is broken by ion bombardment and Cl radical, and the peak of metal Pb in a Pb 4f narrow scan begins to appear upon etching. As increasing additive BCl$_3$content the relative content of oxygen decreases rapidly in contrast with etch rate of PZT thin film. So we though that the etch rate of PZT thin film increased because abundant B and BCl radicals made volatile oxy-compound such as B$_{x}$/O$_{y}$ and/or BClO$_{x}$ bond. We achieved etch profile of about 80$^{\circ}$ at Ar(20)/BCl$_3$(80) gas mixing condition and substrate temperature of 8$0^{\circ}C$TEX>X>.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.406-414
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• 1996

We studied the phase formation and the effect of electrical properties of PZT thin films with changing the oxygen partial pressure in cooling after deposition of PZT thin film by reactive sputtering method. The roughness of thin film increased with decreasing the oxygen partial pressure in cooling due to the evaporation on the surface ofthin films and the grain size was not changed very much. The hysteresis property of PZT thin film was improved toward having a good squareness with increasing the cooling oxygen partial pressure. We observed the decrease of remanent polarization, retained polarization and coercive field with decreasing the oxygen partial pressure. Dielectric constant decreased gradually and internal bias field increased in the measurement of dielectric constant-voltage property with decreasing cooling oxygen partial pressure. We observed the increase of nonswitched polarization in the measurement of field accelerated retention and the decrease of nonswitched polarization with increasing the bias time.

• Journal of the Korean Vacuum Society
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• v.19 no.1
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• pp.52-57
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• 2010

$BiFeO_3/Pb(Zr_{0.52}Ti_{0.48})O_3$(BFO/PZT) multilayer thin films have been prepared on a Pt/Ti/$SiO_2$/Si(100) substrate by chemical solution deposition. BFO single layer, BFO/PZT bilayer and multilayer thin films were studied for comparison. X-ray diffraction analysis showed that the crystal structure of all films was multi-orientated perovskite phase without amorphous and impurity phase. The leakage current density at 500 kV/cm was reduced by approximately four and five orders of magnitude by bilayer and multilayer structure films, compared with BFO single layer film. The low leakage current density leads to saturated P-E hysteresis loops of bilayer and multilayer films. In BFO/PZT multlayer film, saturated remanent polarization of $44.3{\mu}C/cm^2$ was obtained at room temperature at 1 kHz with the coercive field($2E_c$) of 681.4 kV/cm.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.3
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• pp.166-173
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• 2001

Hysteresis loops of the ferroelectric thin films such as PLZT(10/30/70), PLT(10) and PZT(30/70) was simulated using the field-dependent polarization model and compared to the measured loops. In case of PZT(30/70) thin film, as the real saturation or polarization at the applied voltage or larger than 5V appears slack and its value is quite different from the simulated one, it is deduced that the ferroelectric polarization of PZT(30/70) is generated not only by the pure dipoles but also by various electric charges. The drain current of quasi-MFISFET is expressed by using the square-law FET and field-dependent polarization models. The modeling results are analogous to the experimental values. The channel of quasi-MFISFET using PZT(30/70) forms more quickly compared to that of quasi-MFISFET using PLZT(10/30/70) or PLT(10) in the state of 'write' gate voltage of -10V. This may be because the decrease rate of the polarization in the PZT(30/70) thin film is 3~4 times more rapid than that of the polarization in the PLZT(10/30/70) or the PLT(10) thin film in the retention characteristics.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.11a
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• pp.11-11
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• 1994

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.11a
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• pp.128-128
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• 1999