Magnetic Anisotropy in Epitaxial Ni/Cu (100) Thin Films

1993 ◽  
Vol 313 ◽  
Author(s):  
G. Bochi ◽  
C. A. Ballentine ◽  
H. E. Inglefield ◽  
S. S. Bogomolov ◽  
C. V. Thompson ◽  
...  
Keyword(s):  
Thin Films ◽  
Molecular Beam Epitaxy ◽  
Magnetic Anisotropy ◽  
Kerr Effect ◽  
Molecular Beam ◽  
Misfit Strain ◽  
Ex Situ ◽  
Vibrating Sample Magnetometer ◽  
Perpendicular Magnetization

ABSTRACTEpitaxial Ni/Cu (001) films grown on Si (001) by Molecular Beam Epitaxy were studied in-situ using the Surface Magneto-optic Kerr Effect (SMOKE) and ex-situ with a Vibrating Sample Magnetometer (VSM). Perpendicular Magnetization is observed for Ni thicknesses 15 Å ≤ h ≤ 60 Å and fully in-plane magnetization for h ≥ 70 Å when the films are characterized in-situ. The reversal in magnetic anisotropy observed in-situ at 60 Å shifts to 125 Å when the films are exposed to air. 100 Å Ni films deposited on Cu1−x-Nix alloy substrates also show a reversal in magnetic anisotropy as x is changed. These results suggest that changes in magnetic anisotropy correlate with misfit strain accommodation.

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

Properties of Epitaxial SrTiO3 Thin Films Grown on Silicon by Molecular Beam Epitaxy

1999 ◽  
Vol 567 ◽  
Author(s):  
Z. Yu ◽  
R. Droopad ◽  
J. Ramdani ◽  
J.A. Curless ◽  
C.D. Overgaard ◽  
...  
Keyword(s):  
Thin Films ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
High Energy ◽  
State Density ◽  
Unit Cell ◽  
Ex Situ ◽  
Silicon Oxide Layer ◽  
Single Crystalline ◽  
X Ray

ABSTRACTSingle crystalline perovskite oxides such as SrTiO3 (STO) are highly desirable for future generation ULSI applications. Over the past three decades, development of crystalline oxides on silicon has been a great technological challenge as an amorphous silicon oxide layer forms readily on the Si surface when exposed to oxygen preventing the intended oxide heteroepitaxy on Si substrate. Recently, we have successfully grown epitaxial STO thin films on Si(001) surface by using molecular beam epitaxy (MBE) method. Properties of the STO films on Si have been characterized using a variety of techniques including in-situ reflection high energy electron diffraction (RHEED), ex-situ X-ray diffraction (XRD), spectroscopic ellipsometry (SE), Auger electron spectroscopy (AES) and atomic force microscopy (AFM). The STO films grown on Si(001) substrate show bright and streaky RHEED patterns indicating coherent two-dimensional epitaxial oxide film growth with its unit cell rotated 450 with respect to the underlying Si unit cell. RHEED and XRD data confirm the single crystalline nature and (001) orientation of the STO films. An X-ray pole figure indicates the in-plane orientation relationship as STO[100]//Si[110] and STO(001)// Si(001). The STO surface is atomically smooth with AFM rms roughness of 1.2 AÅ. The leakage current density is measured to be in the low 10−9 A/cm2 range at 1 V, after a brief post-growth anneal in O2. An interface state density Dit = 4.6 × 1011 eV−1 cm−2 is inferred from the high-frequency and quasi-static C-V characteristics. The effective oxide thickness for a 200 Å STO film is around 30 Å and is not sensitive to post-growth anneal in O2 at 500-700°C. These STO films are also robust against forming gas anneal. Finally, STO MOSFET structures have been fabricated and tested. An extrinsic carrier mobility value of 66 cm2 V−11 s−1 is obtained for an STO PMOS device with a 2 μm effective gate length.

Study of As and P Incorporation Behavior in GaAsP by Gas-Source Molecular-Beam Epitaxy

1991 ◽  
Vol 222 ◽  
Author(s):  
B. W. Liang ◽  
H. Q. Hou ◽  
C. W. Tu
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
High Energy ◽  
Ex Situ ◽  
Limited Growth ◽  
Group V ◽  
Group Iii ◽  
Gas Source ◽  
Simple Kinetic Model

ABSTRACTA simple kinetic model has been developed to explain the agreement between in situ and ex situ determination of phosphorus composition in GaAs1−xPx (x < 0.4) epilayers grown on GaAs (001) by gas-source molecular-beam epitaxy (GSMBE). The in situ determination is by monitoring the intensity oscillations of reflection high-energy-electron diffraction during group-V-limited growth, and the ex situ determination is by x-ray rocking curve measurement of GaAs1−xPx/GaAs strained-layer superlattices grown under group-III-limited growth condition.

Misfit Strain Relief Beyond the Critical Thickness Using Curvature Measurements and in Situ Characterization of the Magneto-Optic Kerr Effect

1994 ◽  
Vol 356 ◽  
Author(s):  
H. E. Inglefield ◽  
G. Bochi ◽  
C. A. Ballentine ◽  
R. C. O’Handley ◽  
C. V. Thompson
Keyword(s):  
Film Thickness ◽  
Magnetic Anisotropy ◽  
Kerr Effect ◽  
Critical Thickness ◽  
Misfit Strain ◽  
Misfit Dislocations ◽  
Wafer Curvature ◽  
Curvature Measurements ◽  
Magneto Optic

AbstractEpitaxial misfit has been characterized in Ni/Cu/Si (100) as a function of Ni film thickness using wafer curvature measurements. This strain can be related to measurements of magnetic anisotropy made in the deposition system using the magneto-optic Kerr effect. Films were deposited using molecular beam epitaxy (MBE) with varying Ni epilayer thickness between 10 and 1000Å. The change in wafer curvature due to misfit strain was measured using optical interferometry and the strain was calculated using Stoney’s equation. Transmission electron microscopy was used to characterize misfit dislocations at the Ni/Cu interface. It has been determined that misfit strain can have a very strong effect on magnetic anisotropy, particularly in the regime between the critical thickness and complete misfit accommodation, where strain has been found to decrease significantly as a function of film thickness. A critical strain has been determined at which a transition in the direction of magnetization easy axis from perpendicular to the film to in the film plane occurs. This discovery allows the use of Kerr effect measurements to characterize misfit strain in situ.

Magnetic Properties of Epitaxial Mbe-Grown thin Fe3O4 Films on MgO (100)

1995 ◽  
Vol 384 ◽  
Author(s):  
P.A.A. Van Der Heijden ◽  
J.J. Hammink ◽  
PJ.H. Bloemen ◽  
R.M. Wolf ◽  
M.G. Van Opstal ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Molecular Beam Epitaxy ◽  
Single Crystal ◽  
Ferromagnetic Resonance ◽  
Kerr Effect ◽  
Molecular Beam ◽  
Magnetic Behavior ◽  
Optical Kerr Effect ◽  
Magneto Optical Kerr Effect

ABSTRACTCoherent epitaxial Fe3O4 layers in the range of 0 to 400 Å have been grown by molecular beam epitaxy on single crystal MgO(100) substrates. The magnetic properties were studied by local magneto-optical Kerr effect experiments on a wedge shaped Fe3O4 layer, by ferromagnetic resonance and SQUID. The results show that the magnetic behavior of the Fe3O4 thin films resembles bulk Fe3O4 in the investigated thickness range.

In-Situ Growth of Bi-Sr-Ca-Cu-O Thin Films by Molecular Beam Epitaxy

1991 ◽  
pp. 1085-1088 ◽  
Author(s):  
Shigeki Sakai ◽  
Yuji Kasai ◽  
Shunsuke Hosokawa ◽  
Shingo Ichimura
Keyword(s):  
Thin Films ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
In Situ Growth

Ge Nanocrystals Grown on Si(111) by Molecular Beam Epitaxy with and without CaF2 Buffer Layers

1994 ◽  
Vol 358 ◽  
Author(s):  
Peter W. Deelman ◽  
Thomas Thundat ◽  
Leo J. Schowalter
Keyword(s):  
Molecular Beam Epitaxy ◽  
Substrate Temperature ◽  
Molecular Beam ◽  
Buffer Layers ◽  
Ex Situ ◽  
Rheed Pattern ◽  
Island Growth ◽  
Clustering Behavior ◽  
Ge Nanocrystals

ABSTRACTThe Stranski-Krastanov growth mode of Ge thin films on Si and the clustering behavior of Ge on calcium fluoride have been exploited to grow self-assembled nanocrystals by molecular beam epitaxy. The growth of the samples was monitored in situ with RHEED, and they were analyzed ex situ with AFM and RBS. For each system (Ge/Si and Ge/CaF2/Si), the dependence of Ge islanding on substrate temperature and on substrate misorientation was studied. When grown on Si(111) at temperatures between 500°C and 700°C, Ge clusters nucleated at step edges on vicinal wafers and nucleated homogeneously on on-axis wafers. Above 600°C, no transition to a spotty RHEED pattern, which would be expected for island growth, was observed for the vicinal samples. Ge grown at 500°C on on-axis Si(111) formed islands with a relatively narrow size distribution, typically 160nm in diameter and 10nm to 20nm in height. When grown on a CaF2 buffer layer, Ge islands nucleated homogeneously at a substrate temperature of 750°C, resulting in randomly distributed, oblate crystallites approximately 100nm to 200nm in diameter. At 650°C and 700°C, although we still observed many randomly distributed, small crystallites, most islands nucleated at step bunches and had a length scale of over 500nm.

Use of Magneto-Optic Kerr Effect Measurements to Study Strain and Misfit Accommodation in Thin Films of Ni/Cu (100)

1993 ◽  
Vol 308 ◽  
Author(s):  
H.E. Inglefield ◽  
C.A. Ballentine ◽  
G. Bochi ◽  
S.S. Bogomolov ◽  
R.C. O'Handley ◽  
...  
Keyword(s):  
Thin Films ◽  
Kerr Effect ◽  
Molecular Beam ◽  
Magnetic Thin Films ◽  
Fringe Analysis ◽  
High Resolution Tem ◽  
Kinetics Of ◽  
Misfit Accommodation ◽  
Magneto Optic

ABSTRACTWe have detected magnetic transitions in Ni/Cu (100) films as a function of Ni thickness through in situ measurements of the magneto-optic Kerr effect (MOKE). Crystalline quality was monitored using in situ RHEED and Auger electron spectroscopy. Films were deposited by molecular beam epitaxy on silicon wafers and cleaved sodium chloride with varying epitaxial Ni layer thicknesses between 10 and 200 A. High-resolution TEM images of these films indicate decreasing misfit dislocation spacing and decreasing strain as measured by moiré fringe analysis with increasing Ni thickness. These observations have been correlated with changes in magnetic anisotropy as measured by MOKE. MOKE, therefore, may provide a tool for in situ monitoring of the kinetics of misfit accommodation in magnetic thin films.

Optimization of synthesis of the solid solution, Pb(Zr1–xTix)O3 on a single substrate using a high-throughput modified molecular-beam epitaxy technique

2009 ◽  
Vol 24 (1) ◽  
pp. 164-172 ◽  
Author(s):  
P.S. Anderson ◽  
S. Guerin ◽  
B.E. Hayden ◽  
Y. Han ◽  
M. Pasha ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Beam Epitaxy ◽  
High Throughput ◽  
Molecular Beam ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Single Substrate ◽  
Transmission Electron ◽  
Substrate Temperatures

Synthesis of Pb(Zr1–xTix)O3 (PZT) on a single substrate using a high-throughput molecular-beam epitaxy technique was demonstrated. In situ synthesis of crystalline PZT at elevated substrate temperatures could not be achieved, as reevaporation of Pb (PbO) occurred and the partial pressure of O2 was insufficient to prevent formation of a PbPtx phase during deposition. Instead, ex situ postdeposition annealing was performed on PZT deposited at room temperature. Dense single phase PZT was prepared with a compositional range of 0.1 > x > 0.9, for film thicknesses up to 800 nm. Transmission electron microscopy revealed the grain size increased from 50 nm to ∼0.5 μm with increasing Zr-concentration and became more columnar. Raman, x-ray diffraction, and scanning electron microscopy/energy dispersive spectroscopy results revealed a morphotropic phase boundary between rhombohedral and tetragonal phases occurred at x ∼0.4 rather than at x = 0.47 in bulk ceramics. This was attributed to clamping arising from mismatch in thermal expansion between the film and substrate.

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