• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.416-418
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• 2000

Thin films of phase-pure perovskite $(Pb_{0.72}La_{0.28})Ti_{0.93}O_3$ (PLT) were deposited in-situ onto Pt/Ti/$SiO_2$/Si substrates by pulsed laser deposition. We have systematically investigated the variation of grain sizes depending on the process condition. Both in-situ annealing and ex-situ annealing treatments have been compared depending on the annealing time. The grain sizes of PLT thin films were successfully controlled 260 to 350 nm by changing process parameters. Microstructural and electrical properties of the film were investigated by C-V measurement, leakage current measurement and SEM. Two-step process to grow $(Pb_{0.72}La_{0.28})Ti_{0.93}O_3$ (PLT) films was adopted and verified to be useful to enlarge the grain size of the film and to enhance the leakage current characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.861-864
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• 2000

Ferroelectric thin film capacitors with high dielectric constant are important for the application of memory devices. In this work, thin films of PLT(28)(Pb$\sub$0.72/La$\sub$0.28/Ti$\sub$0.93/O$_3$) were fabricated on Pt/Ti/SiO$_2$/Si substrates in-situ annealing and ex-situ annealing have been compared depending on the annealing time. We have systematically investigated the variation of grain sizes depending on the condition of post-annealing and the variation of deposition rate. C-V measurement, ferroelectric properties, leakage current and SEM were performed to investigate the electrical properties and the microstructural properties of Pb(La,Ti)O$_3$.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.367-370
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• 2004

We fabricated PLT(5) thin film on $Pt/TiO_x/SiO_2/Si$ substrate by using sol-gel method and investigated leakage current, switching and retention properties. The leakage current density of PLT(5) thin film was $3.56{\times}10^{-7}A/cm^2$ at 4V. In the examination of switching properties, pulse voltage and load resistance were $2V{\~}5V$ and $50{\Omega}{\~}3.3k{\Omega}$, respectively. Switching time had a tendency to decrease from 520ns to 140ns with the increase of pulse voltage, and also the time was increased from 140ns to $13.7{\mu}s$ with the increase of load resistance. The activation energy obtained from the relation of applied pulse voltage and switching time was about 143kV/cm. The error of switched charge density between hysteresis loop and experiment of polarization switching was about $10\%$. Also, polarization in retention was decreased as much as about $8\%$ after $10^5$s.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1488-1490
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• 1997

$(Pb_{1-x}La_x)Ti_{1-x/4}O_3$ (x=0, 0.02, 0.04, 0.06, 0.08) ceramic thin films were fabricated by Sol-Gel method. A stock solution of (Pb,La)$TiO_3$ with excess Pb 10mol% was made and spin-coated on the Pt/Ti/$SiO_2$/Si substrate at 4000rpm for 30 seconds. Coated specimens were dried on the hot-plate at $350^{\circ}C$ for 10 min and sintered at $500{\sim}750^{\circ}C$ for 1 hour. The dielectric constant, remanent polarization and coercive field of the PLT(6 at.%) thin films sintered at $650^{\circ}C$ were 884, $13.95{\mu}C/cm^2$ and 8.7kV/cm, respectively. Pyroelectric coefficient, figure of merit of pyroelectric current, voltage responsivity and detectivity of PLT(6at.%) thin films were $3.2{\times}10^{-8}\;C/cm^2K$, $1.02{\times}10^{-8}\;C{\cdot}cm/J$, $2.9{\times}10^{-11}\;C{\cdot}cm/J$, $0.29{\times}10^{-8}\;C{\cdot}cm/J$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.170-173
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• 2001

Thin films of phase-pure perovskite (P $b_{0.72}$L $a_{0.28}$) $Ti_{0.93}$ $O_3$(PLT) were deposited in-situ onto Pt/Ti/ $SiO_2$/Si substrates by pulsed laser deposition. We have systematically investigated the variation of grain sizes depending on the process condition. Both in-situ annealing and ex-situ annealing treatments have been compared depending on the annealing time. Two-step process to grow (P $b_{0.72}$L $a_{0.28}$) $Ti_{0.93}$ $O_3$(PLT) films was adopted and verified to be useful to enlarge the grain size of the film and to enhance the leakage current characteristics. The grain sizes of PLT thin films were successfully controlled 260 to 350 nm by changing process parameters. Electrical properties including dielectric constant, ferroelectric characteristics, crystallization and leakage current of PLT thin films were shown to be strongly inf1uenced by grain size. Also PLT thin films on p-type(100) Si substrate will be fabricated by pulsed laser deposition technique using a Nd:YAG laser with different wavelengths of 355, 532 and 1064 nm. Effect of the variation of laser wavelength on dielectric properties will be discussed. Microstructural and electrical properties of the film were investigated by C-V measurement leakage current measurement and SEM.ent and SEM.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.3
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• pp.190-194
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• 2003

Dielectric thin films of (P $b_{0.72}$,L $a_{0.28}$) $Ti_{0.93}$ $O_3$ (PLT(28)) have been deposited on Pt(111)/Ti/ $SiO_2$/Si(100) substrates in-situ by pulsed laser deposition using different annealing and deposition Processes. We have investigated the effect of hydrogen annealing on the ferroelectric properties of PLT thin films and found that the annealing process causes the diffusion of hydrogen into the ferroelectric film resulting in the destruction of polarization. We have tried to form the film by a two-step deposition process In order to improve electrical property. Two-step process to grow PLT films was adopted and verified to be useful to enlarge the grain size of the film and to reduce the leakage current characteristics. Structural properties and electrical properties including dielectric constant, ferroelectric characteristics, and leakage current of PLT thin films were shown to be strongly influenced by grain size. The film deposited by using two-step Process including pre-annealing treatment has a strongly(111) orientation. However, the films deposited by using single -step process with hydrogen annealing process show the smallest grain size. The film deposited by using two-step process including pre-annealing treatment shows the leakage current density of below 10$^{-7}$ A/c $m^2$ for the field of smaller than 100 kV/cm. However, the films deposited by using single-step process with hydrogen annealing process and pre-annealing process show worse leakage current density than the film deposited by using two-step process including pre-annealing treatment.tment.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1236-1238
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• 1997

유전체 PLT(28) ($Pb_{0.72}La_{0.28}Ti_{0.93}O_3$) 박막을 레이저 어블레이션 기법으로 Pt/Ti/$SiO_3$/Si기판을 $500^{\circ}C{\sim}700^{\circ}C$까지 가열한 상태에서 $O_2$분위기에서 증착시켰다. 증착된 박막은 SEM, XRD 등의 구조적 분석을 통하여 $600^{\circ}C$이상에서 증착된 경우, (111)방향으로 우세하게 성장한, 결정성이 양호한 박막임을 확인하였다. 박막의 전기적 특성은, 증착 온도가 $650^{\circ}C$일 때 약 1400정도의 높은 비유전율을 얻었으며, 전하저장밀도는 100[KV/cm]에서 약 9[${\mu}C/cm^2$]이었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.9
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• pp.1717-1723
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• 2007

In this study , quasi-MFISFET (Metal-Ferroelectric-Insulator-Semiconductor FET) devices are fabricated using PLZT(10/30/70), PLT(10), PZT(30/70) thin film and their drain current properties are investigated. It is found that the drain current of quasi-MFISFET is directly influenced by the polarization strength of ferroelectric thin fan. Also, when the gate voltages are ${\pm}5\;and\;{\pm}10V$, the memory windows are 0.5 and 1.3V, respectively. It means that the memory window is changed with the variation of coercive voltage generated by the voltage applied on ferroelectric thin film. The electric field and the leakage current with time delay of PLZT(10/30/70) thin lam are measured to investigate the retention property of MFISFET device. Some material parameters such as current density constant, $J_{ETO}$, electric field dependent factor K and time dependent factor m are obtained. The variation of charge density with time is quantitatively analyzed by using the material parameters.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.9
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• pp.725-728
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• 2000

Ferroelectric thin film capacitors with high dielectric constant are important for the application of memory devices. In this work, We have systematically investigated the variation of grain sizes depending on the process condition of two-step process. Both in-situ annealing and ex-annealing have been compared depending on the annealing time. C-V measurement, ferroelectric properties, leakage current, XRD and SEM were performed to investigate the electircal properties and microstructural properties of Pb(La, Ti)O$_3$ films.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1483-1484
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• 2000

Dielectric thin films of PLT(Pb(La.Ti)O3) for the application of highly integrated memory devices have been deposited on Pt/Ti/SiO2/Si substrates in situ by pulsed laser deposition(PLD). We have systematically investigated the variation of grain sizes depending on the condition of post-annealing and the variation of deposition rate. Both in-situ annealing and ex-situ annealing have been compared depending on the annealing time. C-V measurement, ferroelectric properties, leakage current and SEM were performed to investigate the electrical properties and the microstructural properties of Pb(La,Ti)$O_3$ films.