• 한국재료학회:학술대회논문집
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• 한국재료학회 1999년도 춘계학술발표강연 및 눈문개요집
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• pp.22-22
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• 1999

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 전자세라믹스 센서 및 박막재료 반도체재료 일렉트렛트 및 응용기술
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• pp.52-55
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• 2000

In this study, (Ba,Sr)$TiO_3$(BST) thin films were etched with a magnetically enhanced inductively coupled plasma(MEICP) as a function Ar/$CF_4$ gas mixing ratio. Experiment was done by varying the etching parameters such as rf power, dc bias voltage and chamber pressure. The maximum etch rate of the BST films was 1700 ${\AA}/min$ under $CF_4/(CF_4+Ar)$ of 0.1, 600 W/350 V and 5 mTorr. The selectivity of BST to Pt and PR was 0.6, 0.7, respectively. X -ray photoelectron spectroscopy(XPS) studies shows that there are surface reaction between Ba, Sr, Ti and C, F radicals during the etching. To analyze the composition of surface residue remaining after the etching, films etched with different $CF_4$/Ar gas mixing ratio were investigated using XPS.

• 한국세라믹학회지
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• 제43권6호
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• pp.362-368
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• 2006

Epitaxial $Ba_{0.5}Sr_{0.5}TiO_3$ (BSTO) thin films have been grown on TiN buffered Si (001) substrates by Pulsed Laser Deposition (PLD) method and the effects of substrate temperature and oxygen partial pressure during the deposition on their dielectric properties and crystallinity were investigated. The crystal orientation, epitaxy nature, and microstructure of oxide thin films were investigated using X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Thin films were prepared with laser fluence of $4.2\;J/cm^2\;and\;3\;J/cm^2$, repetition rate of 8 Hz and 10 Hz, substrate temperatures of $700^{\circ}C$ and ranging from $350^{\circ}C\;to\;700^{\circ}C$ for TiN and oxide respectively. BSTO thin-films were grown on TiN-buffered Si substrates at various oxygen partial pressure ranging from $1{\times}10^{-4}$ torr to $1{\times}10^{-5}$ torr. The TiN buffer layer and BSTO thin films were grown with cube-on-cube epitaxial orientation relationship of $[110](001)_{BSTO}{\parallel}[110](001)_{TiN}{\parallel}[110](001)_{Si}$. The crystallinity of BSTO thin films was improved with increasing substrate temperature. C-axis lattice parameters of BSTO thin films, calculated from XRD ${\theta}-2{\theta}$ scans, decreased from 0.408 m to 0.404 nm and the dielectric constants of BSTO epitaxial thin films increased from 440 to 938 with increasing processing oxygen partial pressure.

• Transactions on Electrical and Electronic Materials
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• 제1권4호
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• pp.30-39
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• 2000

The variation of electrical properties of (Ba, Sr)TiO$_3$[BST] thin films deposited of RuO$_2$electrode with (Ba+Sr)/Tr ration was investigated. BST thin films with various (Ba+Sr)/Tr ration were deposited on RuO$_2$/Si substrates using in-situ RF magnetron sputtering. It was found that the electrical properties of BST films depends on the composition in the film. The dielectric constant of the BST films is about 190 at the (Ba+Sr)/Tr ration of 1.0, 1,025 and does not change markedly. But , the dielectric constant degraded to 145 as the (Ba+Sr)/Tr ratio increase to 1.0. In particular, the leakage current mechanism of the films shows the strong dependence on the (Ba+Sr)/Tr ration in the films. At the ration (Ba+Sr)/Tr=1,025, the Al/BST/RuO$_2$ capacitor show the most asymmetric behavior in the leakage current density, vs, electric field plot. It is considered that the leakage current of the (Ba+Sr)/Tr=1,025 thin films is controlled by the battier-Iimited process, i,e, Schottky emission.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.234-234
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• 2008

Chemically homogeneous $Ba_{0.6}Sr_{0.4}TiO_3$ (BST) sols were synthesized using barium acetate, strontium acetate, and titanium isoproxide as starting materials. BST thin films of thickness 340 nm were deposited on Pt/$TiO_2/SiO_2$/Si and alumina substrates using spin coating method. The technique used for the processing of these films was Ultraviolet (UV) sol-gel photoannealing, using phto-sensitivity precursor solutions and UV-assisted rapid thermal processing(UV-RTP). The crystallization behaviour of the BST sols and thin films was studied by differential thermal analysis (DTA) and X-ray diffraction (XRD). Variation of permittivity and dielectric loss were measured in LCR-meter, model HP 4394A.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.845-847
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• 1999

(Ba, Sr)$TiO_3$[BST] thin films were fabricated on Pt/$TiO_2/SiO_2$/Si substrate by RF sputtering. The structural and dielectric properties of the BST thin films were investigated with the deposition time. Increasing the deposition time from 20 min. to 60 min., second phases were decreased, and EST (111), (100), (200) peaks were increased. The relative dielectric constant and dielectric loss of the EST thin films with the thickness of 3000$\AA$ were 300 and 0.018, respectively at 1[kHz]. The relative dielectric constants was decreased and dielectric losses was increased as increasing the frequency.

• 한국전기전자재료학회논문지
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• 제17권8호
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• pp.852-858
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• 2004

An alkoxide-based sol-gel method was used to fabricate $Ba_{0.6}Sr_{0.4}TiO_{3}$thin films doped by Bi from 5 to 20 mol% on a Pt/Ti/$SiO_2$/Sisubstrate. The structural and dielectric properties of BST thin films were investigated as a function of Bi dopant concentration. The dielectric properties of the Bi doped BST films were strongly dependent on the Bi contents. The dielectric constant and dielectric loss of the films decreased with increasing Bi content. However, the leakage current density of the 10 mol% Bi doped $Ba_{0.6}Sr_{0.4}TiO_{3}$ thin film showed the lowest value of 5.13$\times 10^{-7} A/{cm}^2$ at 5 V. The figure of merit (FOM) reached a maximum value of 32.42 at a 10 mol% Bi doped $Ba_{0.6}Sr_{0.4}TiO_{3}$thin films. The dielectric constant, loss factor, and tunability of the 10 mol% Bi doped $Ba_{0.6}Sr_{0.4}Tio_{3}$ thin films were 333, 0.0095, and 31.1%, respectively.

• 한국세라믹학회지
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• 제40권2호
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• pp.198-205
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• 2003

R.F. Magnetron Sputtering법을 이용하여 Pt/Ti/ $SiO_2$/Si기판 위에 seed-layers와 $Ba_{0.66}$S $r_{0.34}$Ti $O_3$박막을 제조하였다. 다양한 기판온도에 따른 BST 박막의 전기적인 특성(정전용량과 누설전류)과 seed-layer층이 BST 박막에 미치는 영향을 조사하였다. BST 박막은 seed-layer층을 삽입함으로써 박막의 결정성이 향상되었고, 박막의 기판온도(결정화온도)도 상당히 낮출 수 있었다. 순수한 BST에 비하여 seed-layer를 삽입한 BST는 높은 유전상수와 낮은 유전손실 및 낮은 누설전류를 가지는 우수한 전기적 특성을 나타내었다. BST 박막의 전기적 특성은 기판온도에 따라 영향을 받고, seed-layer에 의해 향상됨을 알 수 있었다.

• 한국진공학회지
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• 제10권4호
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• pp.416-423
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• 2001

$SrTiO_3$ 박막의 미세구조와 광학적 및 유전적 특성에 대한 열처리 효과들이 조사되었다. $SrTiO_3$ 박막은 RF-마그네트론 스퍼터링 방법에 의하여 상온의 ITO유리 위에 성장되었으며, 성장된 박막들은 산소 분위기의 여러 온도에서 열처리되었다. X선 회절 패턴을 분석한 결과 상온에서 제작된 as-deposited박막은 비정질 상태로 나타났으며, 450-$600^{\circ}C$에서 열처리한 시료에서는 pyrochlore 구조의 결정 피크들이 우세하게 관측되었다. 그리고 $650^{\circ}C$에서 열처리한 시료에서는 perovskite 구조가 우세하게 나타나는 것이 관측되었다. 특히 $650^{\circ}C$에서 열처리한 시료의 경우는 박막의 미세 결정구조 변화와 더불어 광학적 띠간격이 크게 변하는 것이 광투과도 측정으로부터 관측되었다. 그리고 $600^{\circ}C$에서 열처리된 시료의 경우는 $272^{\circ}C$에서 상전이 피크가 관측되는 반면, $650^{\circ}C$에서 열처리된 시료에서는 $310^{\circ}C$ 부근에서 유전 분산이 관측되었다.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 추계총회 및 연구발표회 초록집
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• pp.91.2-91
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• 2003