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  • 1
    Electronic Resource
    Electronic Resource
    Electrical inhomogeneity in Ga-rich undoped GaAs crystals: Dependence on melt stoichiometry and dislocation distribution (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 4140-4148 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Studies have been made of the macroscopic and microscopic electrical inhomogeneity in undoped bulk GaAs single crystals grown from As/As+Ga melt ratios of 0.48–0.45. Microscopic inhomogeneity was characterized by contact resistance line scans and whole wafer anodization, which gives high-resolution two-dimensional images of the low-resistivity p-type regions within the wafers. The resistivity was nonuniform in wafers from 0.48 As/As+Ga crystals, having a W-shaped radial dependence with minima in the 〈110〉 directions and varying by six orders of magnitude across a wafer, whereas it was uniform in low-resistivity wafers from 0.45 As/As+Ga crystals at fractions of melt solidified, g〉0.4. Precise correlation of microscopic inhomogeneity with grown-in linear and cellular arrays of dislocations was obtained in nonuniform wafers, but no correlation with slip dislocations was observed. Anodization images show that the carrier concentration is quantitatively in agreement with a uniform acceptor background compensated by EL2 concentration fluctuations of factors of 2–3 at the dislocation networks. Inhomogeneity variation with g and As/As+Ga ratio is consistent with macroscopic and microscopic decrease in EL2 with melt stoichiometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344975
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  • 2
    Electronic Resource
    Electronic Resource
    Double-crystal x-ray diffraction from Si1−xGex/Si superlattices: Quantification of peak broadening effects (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1781-1783 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Double-crystal x-ray diffraction has been successfully used to study dimensional and compositional variations in Si1−x Gex /Si superlattices. For most samples studied an adequate agreement between theoretical and experimental diffraction profiles is obtained by using a theoretical model (kinematical) which assumes uniform superlattices with abrupt interfaces. In some samples, however, the superlattice-related diffraction peaks reveal an asymmetric broadening which is shown by comparison with dynamical diffraction simulations to be due to a grading in layer compositions and thicknesses throughout the superlattice stack. Detailed analysis of the diffraction data identified a gradual drift of 1.25% in the Ge flux during molecular beam epitaxy (MBE) growth. The MBE system parameters were modified to compensate for this effect and allow the growth of more structurally perfect strained-layer superlattices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101293
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  • 3
    Electronic Resource
    Electronic Resource
    A study of layer composition of InGaAs/InP multiquantum wells grown by metalorganic chemical vapor deposition using double-crystal x-ray diffraction theory and experiment (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 1185-1190 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: InGaAs/InP multiquantum wells grown by metalorganic chemical vapor deposition have been studied by fitting computer simulated theoretical double-crystal x-ray rocking curves to experimental data. It is shown that the technique can identify the carry over of As into the InP barriers and the concentration and distribution of As are determined. The highest concentration of As observed was 21%, which was confined to the first 50 A(ring) of the barrier and fell to 2% towards the following interface. Both the maximum and minimum concentration of As was found to decrease as a function of the pause time between growth of the InGaAs quantum well and the InP barrier layers. These observations were confirmed by secondary ion mass spectrometry (SIMS) and other experimental data on the same material is shown to support the results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.341882
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  • 4
    Electronic Resource
    Electronic Resource
    An analysis of dislocation reduction by impurity hardening in the liquid-encapsulated Czochralski growth of 〈111〉 InP (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 58 (1985), S. 4383-4389 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Excessive impurity additions have been widely used to suppress dislocation generation in the liquid-encapsulated Czochralski (LEC) growth of InP. We have analyzed this approach by means of the quasi-steady-state heat transfer/thermal stress model. A strong motivation for the investigation was provided by the recent measurement of the critical resolved shear stress σCRS of InP as a function of temperature in the range 748–948 °K for several Ge and S concentrations. The experimental data were analyzed by the method of least squares via the usually accepted logarithmic dependence of σCRS on reciprocal temperature. The extrapolated values of σCRS exhibit a monotonic increase with impurity addition at temperatures near the melting point. Introducing the σCRS and realistic estimates of other physical properties (thermal diffusivity, thermal expansion coefficient, elastic constants, etc.) in the thermal stress model, the dislocation distribution pattern in a {111} substrate cut from a 〈111〉 boule was constructed. This necessitated a suitable recasting of the formalism that was previously applicable only to the {100} orientation. The computed dislocation contour maps on {111} wafers display sixfold symmetry resembling the "Star of David,'' in overall agreement with etch-pit patterns. InP crystals 2.5 cm in diameter grown in a standard high ambient temperature gradient but containing a large amount of Ge ((approximately-equal-to)1019 cm−3) are predicted and observed to be dislocation-free. On the other hand, in nominally undoped material a large density of defects is forecast, especially at the periphery, in line with the etchpit configuration. Intermediate doping levels (∼1017 cm−3 Ge, ∼1018 cm−3 S) reduce the density in the core but leave the outer edge essentially unaltered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.335528
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  • 5
    Electronic Resource
    Electronic Resource
    The Microscopy of Bulk-Grown III-V Semiconductor Materials (1987)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Materials Research 17 (1987), S. 123-148 
    Details
    ISSN: 0084-6600
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.ms.17.080187.001011
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  • 6
    Electronic Resource
    Electronic Resource
    A New Phase in a Complex Alloy Steel (1958)
    [s.l.] : Nature Publishing Group
    Nature 182 (1958), S. 1437-1437 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Table l. d spacings of S phase. lattice parameter 11.50 A Intensity d observed h,k,l d calculated VVF 2.784 4,0,0 2.787 F 2.278 4,2,2 2.276 S 2.143 5,1,1 ; 3,3,3 2.144 VS 1.970 4,4,0 1.971 M 1.882 5,3,1 1.885 VF 1.858 6,0,0; 4,4,2 1.858 F 1.763 6,2,0 1.763 F 1.701 5,3,3 1.700 VF 1.680 ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/1821437a0
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  • 7
    Electronic Resource
    Electronic Resource
    The identification of faulted prismatic dislocation loops in single crystals of undoped InP (1981)
    Springer
    Journal of materials science 16 (1981), S. 2867-2876 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract High-voltage transmission electron microscopy has shown that undoped single crystals of indium phosphide, grown by the liquid-encapsulated Czochralski technique, can contain linear arrays of faulted dislocation loops. The plane of the loops is (1 1 0), the fault vector is 1/n [1 1 0] and the Burgers vector of the dislocation loop is 1/n [1 1 0]. A direct correlation has been obtained between these loops and arrays of both ridge and prism features revealed by chemical etching. Sequential use of two etchants has also established a direct link between the faulted dislocation loops and the slip dislocations induced by thermal stresses during crystal growth. A study of a number of crystals grown from differently prepared starting materials suggests that the formation of the loops is associated with departures from stoichiometry and inhibited by the presence of dopant impurities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02402852
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  • 8
    Electronic Resource
    Electronic Resource
    Etch features in Czochralski-grown single crystal indium phosphide (1980)
    Springer
    Journal of materials science 15 (1980), S. 2539-2549 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Two etchants for InP have been used to categorize etch features in both horizontal and vertical sections of InP single crystals grown by the Czochralski liquid encapsulation technique; these are the AB etchant, used extensively for defect analysis in GaAs and another etchant based on a phosphoric acid/hydrobromic acid mixture. The behaviour of these etchants is different but a cross correlation has been made between the types of etch feature produced. Transmission X-ray topography has been used to correlate etch features with dislocations. Nominally undoped crystals and material doped with specific impurities, e.g. Fe, Ge, Zn, have been examined. The principal features produced by etching are pits, ridges and striations. It is shown that the density and distribution of pits and ridges is consistent with these features being dislocation structures and the mechanisms by which they are revealed are discussed in terms of etching rates. The results allow comment to be made upon interface shape and the source of dislocations in InP crystals grown by the Czochralski technique.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00550758
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  • 9
    Electronic Resource
    Electronic Resource
    The identification of stacking faults on {100} and {110} planes in Pd3Ce (1981)
    Springer
    Journal of materials science 16 (1981), S. 831-835 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02402804
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  • 10
    Electronic Resource
    Electronic Resource
    Deformation behaviour of single crystals of InP in uniaxial compression (1980)
    Springer
    Journal of materials science 15 (1980), S. 1469-1477 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The deformation characteristics of indium phosphide (InP) single crystals under uniaxial compression have been examined as a function of strain rate, temperature and orientation. It has been shown that at temperatures below 0.55T m (T m=melting point; 1335 K) the material fractures in a brittle manner whereas at higher temperatures, within the range 0.55 to 0.71T m, plastic deformation occurs by both slip and deformation twinning; above 0.71T m, slip alone is the operative deformation mechanism. The observed operative slip systems are of the type {1 1 1} 〈0 1 1〉 which are characteristic of most Group IIIb-Group Vb compounds. Deformation twinning occurs predominantly on {1 1 1} planes but some activity is also observed on planes of the type {3 4 5}.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00752127
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