scholarly journals In-situ surface technique analyses and ex-situ characterization of Si1-xGex epilayers grown on Si(001)-2 ×1 by molecular beam epitaxy

1994 ◽  
Vol 4 (4) ◽  
pp. 733-740 ◽  
Author(s):  
D. Aubel ◽  
M. Diani ◽  
M. Stoehr ◽  
J. L. Bischoff ◽  
L. Kubler ◽  
...  
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung

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.


1995 ◽  
Vol 187 (2) ◽  
pp. 309-313
Author(s):  
J. M. Gaines ◽  
C. A. Ponzoni

1991 ◽  
Vol 222 ◽  
Author(s):  
B. W. Liang ◽  
H. Q. Hou ◽  
C. W. Tu

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.


1994 ◽  
Vol 358 ◽  
Author(s):  
Peter W. Deelman ◽  
Thomas Thundat ◽  
Leo J. Schowalter

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.


2009 ◽  
Vol 1178 ◽  
Author(s):  
Yi-Lu Chang ◽  
Arya Fatehi ◽  
Feng Li ◽  
Zetian Mi

AbstractWe have performed a detailed investigation of the molecular beam epitaxial (MBE) growth and characterization of InN nanowires spontaneously formed on Si(111) substrates under nitrogen rich conditions. Controlled epitaxial growth of InN nanowires (NWs) has been demonstrated by using an in situ deposited thin (˜ 0.5 nm) In seeding layer prior to the initiation of growth. By applying this technique, we have achieved non-tapered epitaxial InN NWs that are relatively free of dislocations and stacking faults. Such InN NW ensembles display strong photoluminescence (PL) at room temperature and considerably reduced spectral broadening, with very narrow spectral linewidths of 22 and 40 meV at 77 K and 300 K, respectively.


2009 ◽  
Vol 24 (1) ◽  
pp. 164-172 ◽  
Author(s):  
P.S. Anderson ◽  
S. Guerin ◽  
B.E. Hayden ◽  
Y. Han ◽  
M. Pasha ◽  
...  

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.


Author(s):  
J.B. Posthill ◽  
J. Tarn ◽  
T.P. Humphreys ◽  
K. Das ◽  
J.J. Wortman ◽  
...  

Because of several potential applications and advantages afforded by the heteroepitaxial GaAs-on-Silicon material system, several groups world-wide are attempting to grow device-quality GaAs on Si substrates.eg.1 Both metalorganic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) growth techniques have been widely utilized to achieve heteroepitaxial growth. However, certain fundamental materials and growth problems have thus far prevented any group from achieving heteroepitaxial GaAs of a quality similar to that obtainable from bulk GaAs crystals. A high density of threading dislocations, microtwins/stacking faults, antiphase domain boundaries (APBs) and microfissures can form under non-ideal conditions. These defects result, in part, from stresses generated due to the ∼4% lattice mismatch and the different coefficients of thermal expansion between GaAs and Si.2 Ex-situ characterization of this materials system is essential to assess the material quality and to provide direction for future growth experiments. This contribution describes the TEM characterization methodology that we employ to analyze our GaAs grown on Si substrates by MBE.


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