• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.200-201
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• 2007

The SBT($SrBi_2Ta_2O_9$) thin films with $Bi_2O_3$ buffer layer were deposited on Pt/Ti/$SiO_2$/Si substrate by R.F. magnetron sputtering method in order to improve the ferroelectric characteristics. In SBT thin films, the deficiency of bismuth during the process due to its volatility results in an obvious non stoichiometry of the films and the presence of secondary phases. $Bi_2O_3$ buffer layer was found to be effective to achieve the low temperature crystallization and improve the ferroelectric properties of SBT thin films. Ferroelectric properties and crystallinities of SBT thin films with various post annealing of $Bi_2O_3$ buffer layer were observed as various annealing temperature, using X-Ray Diffraction (XRD), scanning electron microscopy (SEM), Keithley 237 and HP 4192A Impedance Analyzer.

• 한국전기전자재료학회논문지
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• 제18권5호
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• pp.439-444
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• 2005

We investigated the structural and electrical properties of BLT films grown on Si covered with $ZrO_{2}$ buffer layer. The BLT thin film and $ZrO_{2}$ buffer layer were fabricated using a metalorganic decomposition method. The electrical properties of the MFIS structure were investigated by varying thickness of the $ZrO_{2}$ layer. AES and TEM show no interdiffusion and reaction that suppressed using the $ZrO_{2}$ film as a buffer layer The width of the memory window in the C-V curves for the MFIS structure decreased with increasing thickness of the $ZrO_{2}$ layer. It is considered that the memory window width of MFIS is not affected by remanent polarization. Leakage current density decreased by about four orders of magnitude after using $ZrO_{2}$ buffer layer. The results show that the $ZrO_{2}$ buffer layers are prospective candidates for applications in MFIS-FET memory devices.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.183-186
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• 2004

The metal-ferroelectric-insulator-semiconductor(MFIS) capacitors were fabricated using a metalorganic decomposition (MOD)method. The $CeO_2$ thin films were deposited as a buffer layer on Si substrate and $Bi_{3.25}La_{0.75}Ti_3O_{12}$ (BLT) thin films were used as a ferroelectric layer. The electrical and structural properties of the MFIS structure were investigated by varying the $CeO_2$ layer thickness. The width of the memory window in the capacitance-voltage (C-V)curves for the MFIS structure decreased with increasing thickness of the $CeO_2$ layer. Auger electron spectroscopy (AES) and transmission electron microscopy (TEM) show no interdiffusion by using the $CeO_2$ film as buffer layer between the BLT film and Si substrate. The experimental results show that the BLT-based MFIS structure is suitable for non-volatile memory field-effect-transistors (FETs) with large memory window.

• 열처리공학회지
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• 제28권6호
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• pp.296-299
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• 2015

$In_2O_3/Ti$ bi-layered films were deposited on glass substrate at room temperature with radio frequency (RF) and direct current (DC) magnetron sputtering to consider the effect of Ti buffer layer on the electrical and optical properties. In a comparison of figure of merit, $In_2O_3$ 90 nm/Ti 10 nm thin films show the higher opto-electrical performance of $3.0{\times}10^{-4}{\Omega}^{-1}$ than that of the $In_2O_3$ single layer films ($2.6{\times}10^{-4}{\Omega}^{-1}$). From the observed results, it is supposed that the $In_2O_3\;90nm/TiO_2$ 10 nm bi-layered films may be an alternative candidate for transparent electrode in a transparent thin film transistor device.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.178.2-178.2
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• 2015

In and Ga doped ZnO (IGZO) films were deposited on 5 nm thick Cu film buffered Polycarbonate (PC) substrates with RF magnetron sputtering and then the effect of Cu buffer layer on the optical and electrical properties of the films was investigated. While IGZO single layer films show the electrical resistivity of $1.2{\times}10-1{\Omega}cm$, IGZO/Cu bi-layered films show a lower resistivity of $1.6{\times}10-3{\Omega}cm$. Although the optical transmittance of the films in a visible wave length range is deteriorated by Cu buffer layer, IGZO films with 5 nm thick Cu buffer layer show the higher figure of merit of $2.6{\times}10-4{\Omega}-1$ than that of the IGZO single layer films due to the enhanced opto-electrical performance of the IGZO/Cu bi-layered films.

• Transactions on Electrical and Electronic Materials
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• 제14권5호
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• pp.242-245
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• 2013

Sn-doped $In_2O_3$ (ITO) thin films were prepared by radio frequency magnetron sputtering without intentional substrate heating on bare glass and $TiO_2$-deposited glass substrates to investigate the effect of a $TiO_2$ buffer layer on the electrical and optical properties of ITO films. The thicknesses of $TiO_2$ and ITO films were kept constant at 5 and 100 nm, respectively. As-deposited ITO single layer films show an optical transmittance of 75.9%, while $ITO/TiO_2$ bi-layered films show a lower transmittance of 76.1%. However, as-deposited $ITO/TiO_2$ films show a lower resistivity ($9.87{\times}10^{-4}{\Omega}cm$) than that of ITO single layer films. In addition, the work function of the ITO film is affected by the $TiO_2$ buffer layer, with the $ITO/TiO_2$ films having a higher work-function (5.0 eV) than that of the ITO single layer films. The experimental results indicate that a 5-nm-thick $TiO_2$ buffer layer on the $ITO/TiO_2$ films results in better performance than conventional ITO single layer films.

• 한국세라믹학회지
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• 제39권4호
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• pp.377-385
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• 2002

Metal-Ferroelectric-Insulator-Semiconductor(MFIS) 구조의 적용하기 위해 R. F. 마그네트론 스퍼터를 이용하여 p-type Si(111) 기판 위에 $ZrO_2$와 $SrBi_2Ta_2O_9$ 박막을 증착하였다. SBT 박막은 $ZrO_2$ 완충층을 삽입함으로써 MFIS 구조의 전기적인 특성이 향상되었다. $ZrO_2$ 박막의 두께를 고정하고 SBT 박막의 두께를 160nm에서 220nm으로 변화시키면서 윈도우 메모리를 3-9V의 범위에서 측정하였다. Pt/SBT(160nm)/$ZrO_2$(20nm)/Si의 조건에서 최대 2.2V 메모리 윈도우 값을 얻을 수 있었으며 이 메모리 윈도우 값은 실제 적용되는 저전압 NDRO-FRAM 구동에 충분한 값이다.

• Progress in Superconductivity
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• 제11권2호
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• pp.100-105
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• 2010

Reel-to-reel deposition of $Y_2O_3$ has been performed on Ni-5%W metal substrates using the RF-sputtering method. The epitaxial orientation of $Y_2O_3$ buffer layers to the base bi-axially textured substrate was well identified using ${\theta}-2{\theta}$, out-of-plane ($\omega$), and in-plane ($\phi$) scans in X-ray diffraction analysis. The optimization of $Y_2O_3$ seed layers in reel-to-reel fashion were investigated varying the deposition temperature, sputtering power, and pressure for its significant roles for the following buffer stacks and superconducting layers. $Y_2O_3$ were all grown epitaxially on bi-axially textured metal substrates at 380 watts and 5 mTorr in the temperature range of $600-740^{\circ}C$ with higher $Y_2O_3$ (400) intensities at ${\sim}710^{\circ}C$. It was found that the $\Delta\omega$ values were $1-2^{\circ}$ lower but the $\Delta\phi$ values were above $1^{\circ}$ higher than that of Ni-W substrates. As the sputtering power increased from 340 to 380 watts, $\Delta\omega$ and $\Delta\phi$ values showed decreased tendency. Even in the small window of deposition pressure of 3-7 mTorr, the $Y_2O_3$ (400) intensities increased and $\Delta\omega$ and $\Delta\phi$ values were reduced as sputtering pressure increased.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.129-132
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• 2003

Yttria stabilized zirconia (YSZ) buffer layers were deposited by a metal organic chemical vapor deposition (MOCVD) technique using single liquid source for the application of YBa$_2$Cu$_3$$O_{7-x}$ (YBCO) coated conductor. Y:Zr mole ratio was 0.2:0.8, and tetrahydrofuran (THF) was used as a solvent. The (100) single crystal MgO substrate was used for searching deposition condition. Bi-axially oriented CeO$_2$ and NiO films were fabricated on {100}〈001〉 Ni substrate by the same method and used as templates. At a constant working pressure of 10 Torr, the deposition temperatures (660~80$0^{\circ}C$) and oxygen flow rates (100~500 sccm) were changed to find the optimum deposition condition. The best (100) oriented YSZ film on MgO was obtained at 74$0^{\circ}C$ and $O_2$ flow rate of 300 sccm. For YSZ buffer layer with this deposition condition on CeO$_2$/Ni template, full width half maximum (FWHM) values of the in-plane and out-of-plane alignments were 10.6$^{\circ}$ and 9.8$^{\circ}$, respectively. The SEM image of YSZ film on CeO$_2$/Ni showed surface morphologies without microcrack.k.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.180-180
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• 2003

FRAM (Ferroelectric Random Access Memory)은 DRAM(Dynamic Random Access Memory)in 커패시터 재료을 상유전체 물질에서 강유전체 물질로 대체하여 전원 공급이 차단되어도 정보를 기억할 수 있고, 데이터의 고속처리가 가능하고 저소비전력과 집적화가 뛰어난 차세대 메모리 소자이다. 본 연구에서는 n-Well/P-Si(100) 기판위에 $Y_2$O$_3$ 박막을 중간층 (buffer layer)으로 사용하여 (Bi,La) Ti$_3$O$_{12}$ (BLT) 강유전체 박막을 졸-겔 방법으로 형성하여 MFM(I)S(Metal Ferroelectric Metal (Insulation) Silicon) 구조의 커패시터 및 전계효과형 트랜지스터(Field Effect Transistor) 소자를 제작하였다. 제작된 소자에 대해 형상학적, 전기적 특성을 조사, 분석하였다.