• 제목/요약/키워드: epitaxial film

검색결과 269건 처리시간 0.021초

Co-Si계의 동시증착과 고상반응시 상전이 및 $CoSi_2$ 층의 저온정합성장 (Phase sequence in Codeposition and Solid State Reaction of Co-Si System and Low Temperature Epitaxial Growth of $CoSi_2$ Layer)

  • 박상욱;심재엽;지응준;최정동;곽준섭;백홍구
    • 한국진공학회지
    • /
    • 제2권4호
    • /
    • pp.439-454
    • /
    • 1993
  • The phase sequence of codeposited Co-Si alloy and Co/si multilayer thin film was investigated by differential scanning calormetry(DSC) and X-ray diffraction (XRD) analysis, The phase sequence in codeposition and codeposited amorphous Co-Si alloy thin film were CoSilongrightarrow Co2Si and those in Co/Si multilayer thin film were CoSilongrightarrowCo2Silongrightarrow and CoSilongrightarrowCo2Si longrightarrowCoSilongrightarrowCoSi2 with the atomic concentration ration of Co to Si layer being 2:1 and 1:2 respectively. The observed phase sequence was analyzed by the effectvie heat of formatin . The phase determining factor (PDF) considering structural facotr in addition to the effectvie heat of formation was used to explain the difference in the first crystalline phase between codeposition, codeposited amorphous Co-Si alloy thin film and Co/Si multilayer thin film. The crystallinity of Co-silicide deposited by multitarget bias cosputter deposition (MBCD) wasinvestigated as a funcion of deposition temperature and substrate bias voltage by transmission electron microscopy (TEM) and epitaxial CoSi2 layer was grown at $200^{\circ}C$ . Parameters, Ear, $\alpha$(As), were calculate dto quantitatively explain the low temperature epitaxial grpwth of CoSi2 layer. The phase sequence and crystallinity had a stronger dependence on the substrate bias voltage than on the deposition temperature due to the collisional daxcade mixing, in-situ cleannin g, and increase in the number of nucleation sites by ion bombardment of growing surface.

  • PDF

Epitaxial Growth of MgO and CoFe/MgO on Ge(001) Substrates by Molecular Beam Epitaxy

  • Jeon, Kun-Rok;Park, Chang-Yup;Shin, Sung-Chul
    • 한국자기학회:학술대회 개요집
    • /
    • 한국자기학회 2009년도 정기총회 및 동계학술연구발표회
    • /
    • pp.190-190
    • /
    • 2009
  • We report the epitaxial growth of MgO and CoFe/MgO on Ge (001) substrates using molecular beam epitaxy. It was found that the epitaxial growth of a MgO film on Ge could be realized at a low growth temperature of $125{\pm}5^{\circ}C$ and the MgO matches the Ge with a cell ratio of $\sqrt{2}$:1 which renders MgO rotated by $45^{\circ}$ relative to Ge. In-situ and ex-situ structural characterizations reveal the epitaxial crystal growth of bcc CoFe/MgO on Ge with the in-plane crystallographic relationship of CoFe(001)[100] || MgO(001)[110] || Ge(001)[100], exhibiting sharp interfaces in the (001) matching planes. The saturation magnetization of the sample is $1430{\pm}20$ emu/cc, which is comparable to the value of bulk CoFe.

  • PDF

Tunable microwave device에 사용될 수 있는 $(Ba,Sr)TiO_{3}$ 박막의 유전특성 향상에 관한 연구 (Enhanced dielectric properties of $(Ba,Sr)TiO_{3}$ thin films applicable to tunable microwave devices)

  • 박배호
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
    • /
    • pp.73-76
    • /
    • 2001
  • We deposited epitaxial $Ba_{0.6}Sr_{0.4}TiO_{3}(BST)$ films having thickness of 400 nm on MgO(001) substrates, where a 10 nm thick $Ba_{1-x}Sr_{x}TiO_{3}$ (x = 0.1 - 0.7) interlayer was inserted between BST and MgO to manipulate the stress of the BST films. Since the main difference of those epitaxial BST films was the lattice constant of the interlayers, we were very successful in controlling the stress of the BST films. BST films under small tensile stress showed larger dielectric constant than that without stress as well as those under compressive stress. Stress relaxation was investigated using epitaxial BST films with various thicknesses grown on different interlayers. For BST films grown on $Ba_{0.7}Sr_{0.3}TiO_{3}$ interlayers, the critical thickness was about 600 nm. On the other hand, the critical thickness of single-layer BST film was less than 100 nm.

  • PDF

Tunable microwave device에 사용될 수 있는 (Ba,Sr)$TiO_3$ 박막의 유전특성 향상에 관한 연구 (Enhanced dielectric properties of (Ba.Sr)$TiO_3$ thin films applicable to tunable microwave devices)

  • 박배호
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2001년도 추계학술대회 논문집
    • /
    • pp.73-76
    • /
    • 2001
  • We deposited epitaxial $Ba_{0.6}$S $r_{0.4}$Ti $O_3$(BST) films having thickness of 400 nm on MgO(001) substrates, where a 10 nm thick $Ba_{1-x}$S $r_{x}$Ti $O_3$(x=0.1-0.7) interlayer was inserted between BST and MgO to manipulate the stress of the BST films. Since the main difference of those epitaxial BST films was the lattice constant of the interlayers, we were very successful in controlling the stress of the BST films. BST films under small tensile stress showed larger dielectric constant than that without stress as well as those under compressive stress. Stress relaxation was investigated using epitaxial BST films with various thicknesses grown on different interlayers. For BST films grown on $Ba_{0.7}$S $r_{0.3}$Ti $O_3$ interlayers, the critical thickness was about 600 nm. On the other hand, the critical thickness of single-layer BST film was less than 100 nm.00 nm.m.m.m.

  • PDF

On increasing the homogeneity of the properties of epitaxial layers grown from the gas phase, taking into account natural convection and changes in the rate of chemical interaction between materials

  • Pankratov, E.L.
    • Advances in materials Research
    • /
    • 제9권2호
    • /
    • pp.155-170
    • /
    • 2020
  • In this paper, using the recently introduced analytical approach for the analysis of mass and heat transfer during film growth in reactors for epitaxy from the gas phase, these processes are analyzed taking into account natural convection and the possibility of changing the rate of chemical interaction between reagents. As a result of the analysis, the conditions under which the homogeneity of the grown epitaxial layers increases with a change in the values of the parameters of the growth process are formulated.

Atomically sculptured heart in oxide film using convergent electron beam

  • Gwangyeob Lee;Seung-Hyub Baek;Hye Jung Chang
    • Applied Microscopy
    • /
    • 제51권
    • /
    • pp.1.1-1.2
    • /
    • 2021
  • We demonstrate a fabrication of an atomically controlled single-crystal heart-shaped nanostructure using a convergent electron beam in a scanning transmission electron microscope. The delicately controlled e-beam enable epitaxial crystallization of perovskite oxide LaAlO3 grown out of the relative conductive interface (i.e. 2 dimensional electron gas) between amorphous LaAlO3/crystalline SrTiO3.

Magnetisation reversal dynamics in epitaxial Fe/GaAs(001) and Fe/InAs(001) thin films

  • Lee, W. Y.;K. H. Shin;Kim, H. J.
    • 한국자기학회:학술대회 개요집
    • /
    • 한국자기학회 2000년도 International Symposium on Magnetics The 2000 Fall Conference
    • /
    • pp.230-238
    • /
    • 2000
  • We present the magnetisation reversal dynamics of epitaxial Fe thin films grown on GaAs(001) and InAs(001) studied as a function of field sweep rate in the range 0.01-160 kOe/s using magneto-optic Kerr effect (MOKE). For 55 and 250 ${\AA}$ Fe/GaAs(001), we find that the hysteresis loop area A follows the scaling relation A ∝ H$\^$${\alpha}$/ with ${\alpha}$=0.03∼0.05 at low sweep rates and 0.33-0.40 at high sweep rates. For the 150 ${\AA}$ Fe/InAs(001) film, ${\alpha}$ is found to be ∼0.02 at low sweep rates and ∼0.17 at high sweep rates. The differing values of ${\alpha}$ are attributed to a change of the magnetisation reversal process with increasing sweep rate. Domain wall motion dominates the magnetisation reversal at low sweep rates, but becomes less significant with increasing sweep rate. At high sweep rates, the variation of the dynamic coercivity H$\sub$c/ is attributed to domain nucleation dominating the reversal process. The results of magnetic relaxation studies for easy-axis reversal are consistent with the sweeping of one or more walls through the entire probed region (∼100 $\mu\textrm{m}$). Domain images obtained by scanning Kerr microscopy during the easy cubic axis reversal process reveal large area domains separated by zigzag walls.

  • PDF

졸-겔법을 이용한 Epitaxial Bismuth Titanate 박막의 제조 (Preparation of epitaxial bismuth titanate thin films by the sol-gel process)

  • 김상복;이영환;윤연흠;황규석;오정선;김병훈
    • 한국결정성장학회지
    • /
    • 제13권2호
    • /
    • pp.56-62
    • /
    • 2003
  • 졸-겔법을 이용하고 금속 나프테네이트를 출발원료로 사용하여 $SrTiO_3$(100), $LaA1O_3$(100) 및 MgO(100) 기판 위에 에피탁샬 $Bi_4Ti_3O_{12}$ 박막을 제조하였다. 코팅된 전구막은 $500^{\circ}C$에서 10분간 전열처리 하였고, $750^{\circ}C$에서 30분간 최종 열처리를 행하였다. 박막의 결정화도는 X-선회절 분석법 ($\theta$-2$\theta$ 스캔과 $\beta$ 스캔)으로 조사하였고, 표면 미세구조와 거칠기를 field emission-scanning electron microscope와 atomic force microscope를 이용하여 각각 분석하였다. MgO(100) 기판 위에 제조한 박막은 모든 기판 중에서 가장 낮은 결정화도와 면내 배향성을 보였다. 가장 낮은 결정화도와 배향성을 보인 MgO(100) 기판위의 박막은 침상 형태로 성장한 반면, 결정성과 배향성이 좋은 $LaA1O_3$(100)과 $SrTiO_3$(100) 기판위의 박막들은 원형의 입자 성장 형태를 보이고 있었다.