• 한국전기전자재료학회논문지
• /
• 제12권1호
• /
• pp.56-61
• /
• 1999

Highly conductive oxide films of BaRuO$_3$ have been grown heteroepitaxially on (100) LaAlO$_3$ single crystalline substrates by using pulsed laser deposition. The films are c-axis oriented with an in-plane epitaxial relationship of <010><100>BaRuO$_3$ // <110>LaAlO$_3$. Atomic force microscopy (AFM) observation shows that they consist of a fine-arranged network of grains and have a mosaic microstructure. Generally temperature-dependent resistivity shows the transition from metallic curve to semiconductor-metallic twofold curve by the deposition conditions for Ru oxide based materials like SrRuO$_3$, CaRuO$_3$, BaRuO$_3$, etc.. This twofold curve comes from the structural similarity of Ru oxide based materials including BaRuO$_3$. We find that the distance of Ru-Ru bonding in the unit cell of BaRuO$_3$ as well as the grain boundary scattering could be the two important causes of these interesting conductive properties.

• Progress in Superconductivity
• /
• 제11권2호
• /
• pp.141-146
• /
• 2010

Phase stability diagram and boundary of a- and c-axis orientation of $SmBa_2Cu_3O_{7-y}$ (SmBCO) thin films grown by pulsed laser deposition (PLD) were reported with studies based on x-ray diffraction [1]. Four different samples are systematically analyzed: normal c-axis oriented orthorhombic $SmBa_2Cu_3O_{7-y}$, a-axis oriented $SmBa_2Cu_3O_{7-y}$, c-axis oriented orthorhombic $SmBa_2Cu_3O_{7-y}$ with $Sm_2BaCuO_5$ phase, and a mixture with c-axis oriented orthorhombic $SmBa_2Cu_3O_{7-y}$ and anomalously long-c tetragonal $SmBa_2Cu_3O_x$. Raman scattering spectroscopy equipped with polarization analysis elucidates the crystal orientation and the origin of the growth of the materials. It indicates that the technique can be used for quality control of conductor manufacturing processes as well as for enhancement of the materials properties.

• 대한전자공학회논문지SD
• /
• 제45권7호
• /
• pp.32-36
• /
• 2008

본 연구에서는 펄스 레이저 법으로 200 mTorr 의 산소 분압에서 기판 온도를 $200^{\circ}C$ 에서 $600^{\circ}C$ 까지 변화시켜 가며, quartz 기판 위에 $In_2O_3-ZnO$ 박막을 제작하여 광학적 및 전기적 특성을 조사하였다. XRD 측정을 통해 $In_2O_3-ZnO$ 박막이 다결정 상태인 것을 알 수 있었으며, 기판 온도가 $500^{\circ}C$로 증가함에 따라 $35.5^{\circ}$ 부근의 $In_2O_3$ (400) 피크는 감소한 반면 $30.6^{\circ}$ 부근의 $In_2O_3$ (222) 피크는 증가했다. 박막의 표면을 AFM 으로 조사한 결과, round type 의 결정립들이 관찰되었으며 표면 거칠기 값은 $500^{\circ}C$에서 제작한 박막에서 가장 낮은 값 (6.15 nm) 을 나타내었다. 모든 $In_2O_3-ZnO$ 박막이 가시광 영역에서 평균 82% 이상의 투과율을 보였다. 또, $500^{\circ}C$에서 제작한 $In_2O_3-ZnO$ 박막에서 가장 높은 캐리어 농도 ($2.46{\times}10^{20}cm^{-3}$) 값과 가장 낮은 비저항 ($1.36{\times}10^{-3}{\Omega}cm$) 값을 나타내었다.

• 대한전자공학회논문지SD
• /
• 제44권5호
• /
• pp.15-20
• /
• 2007

펄스 레이저 증착법을 이용하여 ZnO 박막을 quartz 기판 위에 증착하였으며, 기판 온도에 따른 박막의 구조적 및 광학적 특성을 조사하였다. 기판 온도 변화에 관계없이 모든 박막이 (002) 방향으로 성장하였으며, 400 $^{\circ}C$ 에서 반가폭은 0.24$^{\circ}$로 가장 우수한 결정성을 갖는 박막이 제작되었다. 또, 박막의 발광 특성을 조사한 결과, 모든 박막에서 UV 발광 피크와 deep-level 발광 피크가 관찰되었으며, 기판 온도에 따른 발광 피크의 변화가 관찰되었다. 가장 우수한 UV 발광 특성은 400 $^{\circ}C$ 에서 관찰되었으며, 반가폭은 14 nm 였다. 기판 온도에 무관하게 가시광 영역에서 약 85 % 정도의 투과도를 나타내었다. 투과도 측정을 통하여 얻은 광학 밴드갭 에너지와 UV 발광 중심 값을 비교한 결과, 두가지 결과 값들이 서로 유사한 값을 나타냈다. 이로부터 UV 발광 중심 값이 ZnO 의 near band edge emission 을 나타낸다는 사실을 알 수 있었다.

• 한국초전도ㆍ저온공학회논문지
• /
• 제16권2호
• /
• pp.1-6
• /
• 2014

The five-year national project in Japan for R&D of coated conductors and applications, named as the Materials and Power Applications of Coated Conductors (M-PACC) project, was finished at the end of FY2013. The project consists of four sub-themes as cable, transformer, SMES and coated conductors. In the theme of coated conductors, the fabrication process had been developed to satisfy the requirements from the applications such as in-field $I_c$ performance, low AC loss in the long tapes etc. Through the project, the remarkable progress was achieved as follows; a high in-field minimum $I_c$ value over 54A/cm-width under 3T at 77K was realized in a 200m long EuBCO tape with artificial pinning centers of $BaHfO_3$ by the pulsed laser deposition (PLD) technique on the IBAD template. On the other hand, the AC loss reduction was confirmed in the tapes fabricated by both PLD and the metal organic deposition (MOD) techniques by scribing 100m tapes into 10-filamments. Additionally, the mechanism of the delamination phenomenon was systematically investigated and the strength was improved by eliminating the origins of the weak points in the films. Through the development, all targeted goals were accomplished and the several results were appreciated as a world champion data.

• 한국초전도ㆍ저온공학회논문지
• /
• 제10권2호
• /
• pp.16-19
• /
• 2008

Angular dependence of critical current density of SmBCO coated conductor fabricated by co-evaporation method was investigated. For comparison, three samples were fabricated by a co-evaporation method and one sample was fabricated by a pulsed laser deposition process. The deposition system, named EDDC (Evaporation using Drum in Dual Chambers), is a batch type co-evaporation system, which is composed of reaction chamber and evaporation chamber. The normalized critical current density ratio ($I_c/I_c$(H//ab-plane)) of EDDC-SmBCO samples was found to be higher than that of PLD-YBCO sample in the whole range of angle. While the EDDC-SmBCO samples evidently had a peak at the angle of H//c-axis in the plot of the angular dependence of critical current, the normalized critical current of PLD-YBCO sample decreased monotonically without any peak as angle increased. The field dependence of critical current under the magnetic field parallel to the normal direction of those samples showed similar aspect in the range of $0\;G{\sim}5000\;G$.

• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
• /
• pp.66-69
• /
• 2000

본 연구에서는 STO(100) 기판 위에 PLD법으로 YBCO 박막을 제작할 때, YBCO 상과 outgrowth의 형성과정과 구조 등을 관찰하였다. 증착의 각 과정별로 박막의 표면 및 단면을 AFM과 SEM으로 관찰한 결과, YBCO 상은 작은 씨앗에서부터 계속 성장해 가며, YBCO 상은 구조를 약 한층 정도 형성하는 불과 10 ${AA}$ 정도만 증착되어도 YBCO의 XRD 피크를 보인다. 반면에 생성되며, YBCO처럼 작은 씨앗에서 서서히 성장해 가는 것은 아니라고 생각된다.

• 한국재료학회지
• /
• 제10권12호
• /
• pp.807-811
• /
• 2000

MFISFET (Metal-ferroelectric-nsulator-semiconductor-field effect transistor)에의 적용을 위해 CeO$_2$와 SrBi$_2$Ta$_2$O$_{9}$ 박막을 각각 r.f. sputtering 및 pulsed laser ablation법으로 제조하였다. CeO$_2$ 박막은 증착시 스퍼터링개스비 (Ar:O$_2$)에 따른 특성을 고찰하였다. Si(100) 기판 위에 $700^{\circ}C$에서 증착된 CeO$_2$ 박막들은 (200)방향으로 우선방향성을 가지고 성장하였고 $O_2$ 개스량이 증가함에 따라 박막의 우선방향성, 결정립도 및 표면거칠기는 감소하였다. C-V특성에서는 Ar:O$_2$가 1 : 1인 조건에서 제조된 박막이 가장 양호한 특성을 보였다. 제조된 박막들의 누설전류값은 100kV/cm의 전계에서 $10^{-7}$ ~$10^{-8}$ A의 차수를 보였다. CeO$_2$/Si 기판위에 성장된 SBT는 다결정질상의 치밀한 구조를 가지고 성장을 하였다 80$0^{\circ}C$에서 열처리된 SBT박막으로 구성된 MFIS구조의 C-V 특성에서 memory window 폭은 0.9V를 보였으며 5V에서 4$\times$$10^{-7}$ A/$\textrm{cm}^2$의 누설전류밀도를 보였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.254-254
• /
• 2016

Tin dioxide (SnO2) thin film is one of the most important n-type semiconducting materials having a high transparency and chemical stability. Due to their favorable properties, it has been widely used as a base materials in the transparent conducting substrates, gas sensors, and other various electronic applications. Up to now, SnO2 thin film has been extensively studied by a various deposition techniques such as RF magnetron sputtering, sol-gel process, a solution process, pulsed laser deposition (PLD), chemical vapor deposition (CVD), and atomic layer deposition (ALD) [1-6]. Among them, ALD or plasma-enhanced ALD (PEALD) has recently been focused in diverse applications due to its inherent capability for nanotechnologies. SnO2 thin films can be prepared by ALD or PEALD using halide precursors or using various metal-organic (MO) precursors. In the literature, there are many reports on the ALD and PEALD processes for depositing SnO2 thin films using MO precursors [7-8]. However, only ALD-SnO2 processes has been reported for halide precursors and PEALD-SnO2 process has not been reported yet. Herein, therefore, we report the first PEALD process of SnO2 thin films using SnCl4 and oxygen plasma. In this work, the growth kinetics of PEALD-SnO2 as well as their physical and chemical properties were systemically investigated. Moreover, some promising applications of this process will be shown at the end of presentation.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.319-319
• /
• 2013

Even though the fabrication methods of metal oxide based thin film capacitor have been well established such as RF sputtering, Sol-gel, metal organic chemical vapor deposition (MOCVD), ion beam assisted deposition (IBAD) and pulsed laser deposition (PLD), an applicable capacitor of printed circuit board (PCB) has not realized yet by these methods. Barium Strontium Titanate (BST) and other high-k ceramic oxides are important materials used in integrated passive devices, multi-chip modules (MCM), high-density interconnect, and chip-scale packaging. Thin film multi-layer technology is strongly demanded for having high capacitance (120 nF/$mm^2$). In this study, we suggest novel multi-layer thin film capacitor design and fabrication technology utilized by plasma assisted deposition and photolithography processes. Ba0.6Sr0.4TiO3 (BST) was used for the dielectric material since it has high dielectric constant and low dielectric loss. 5-layered BST and Pt thin films with multi-layer sandwich structures were formed on Pt/Ti/$SiO_2$/Si substrate by RF-magnetron sputtering and DC-sputtering. Pt electrodes and BST layers were patterned to reveal internal electrodes by photolithography. SiO2 passivation layer was deposited by plasma-enhanced chemical vapor deposition (PE-CVD). The passivation layer plays an important role to prevent short connection between the electrodes. It was patterned to create holes for the connection between internal electrodes and external electrodes by reactive-ion etching (RIE). External contact pads were formed by Pt electrodes. The microstructure and dielectric characteristics of the capacitors were investigated by scanning electron microscopy (SEM) and impedance analyzer, respectively. In conclusion, the 0402 sized thin film multi-layer capacitors have been demonstrated, which have capacitance of 10 nF. They are expected to be used for decoupling purpose and have been fabricated with high yield.