Observation of coherent hybrid reflection with synchrotron radiation

High resolution synchrotron radiation has been used to investigate the occurrence of coherent hybrid reflections (CHR) in the In0.49Ga0.51P/GaAs(001) structure. Several phi scans at the 002 layer reflection were carried out. The scanned phi intervals are correlated by the axis symmetry and [001] should present the same pattern. A break in the symmetry is observed due to constructive/destructive interference of the hybrid amplitudes with the amplitude from the 002 layer reflection. The effects of substrate miscut and interface distance are taken into account to explain the observed patterns. The application of CHR as a high sensitive tool to analyze epitaxial growth is discussed. (C) 1998 American Institute of Physics. [S0003-6951(98)03841-8].73152194219

X-ray multiple diffraction phenomenon in the evaluation of semiconductor crystalline perfection

In this work, a method that takes advantage of the three-dimensional nature of the X-ray multiple-diffraction (MD) phenomenon for evaluating the crystalline perfection of semiconductors is proposed. The energy-transfer process among the MD beams can occur in a kinematical (secondary extinction) or a dynamical (primary extinction) regime. The effects that each regime can have on MD Bragg condition are theoretically investigated. The method provides information on size and misorientation of perfect-crystal regions as well as on the probability of interaction between them. The perfection of GaAs and Ge (001) surfaces after mechanical and/or chemical polishing has been investigated with this method and, as an extension of its applicability, porous silicon and GaAs (001) with Se ions implanted were also investigated.29444645

ANALYSIS OF INTERFACIAL MISFIT DISLOCATION BY X-RAY MULTIPLE DIFFRACTION

We have developed a new method to analyze the stress state of heteroepitaxial systems using X-ray multiple diffraction (MD). A fitting program extends the MD theory for mosaic crystals to provide the position and profile of the normal and hybrid MD peaks. We use surface secondary beams in order to achieve high resolution in intensity and peak position. These conditions together with the absorption involved in the LS hybrid reflections enable us to test the stress state of the layer by determining the misfit dislocation and the degree of cohesion between the buffer and epitaxial layers. Here, the method was applied in the analysis of thin (500 Angstrom) and thick (1.2 mu m) GaAs layers grown by Vacuum Chemical Epitaxy (VCE) on Si (001).88646546

Sensitivity of Bragg surface diffraction to analyze ion-implanted semiconductors

A special case of the x-ray multiple diffraction phenomenon, the Bra,og surface diffraction (BSD), has been investigated under lattice damage due to ion implantation in GaAs (001) samples. The BSD profile is very sensitive to the diffraction regime (dynamical or kinematical) and provides information regarding crystalline perfection and lattice strains in both directions-parallel and perpendicular-to the sample surface. Results from grazing-incidence x-ray diffraction and are also reported. (C) 1997 American Institute of Physics.71182614261

AU AND AU-ZN CONTACTS ON P-GASB AND THE CHARACTERISTICS OF THE INTERFACES

We analyse the specific contact resistance rho(C) and the interfacial microstructural characteristics (by Auger electron spectroscopy and X-ray diffraction) of Au and AuZn contacts on p-GaSb. The experiments showed that rho(C) hardly depends on the inclusion of Zn in the metallic film or on the annealing processes, at least for the carrier concentrations available (p greater-than-or-equal-to 1.6 x 10(17) cm-3). However, the dependence of rho(C) on the acceptor concentration leads us to conclude that field emission is the principal conduction mechanism, The efficacy of an Ar glow discharge in considerably reducing the oxide present at the GaSb substrate is demonstrated. We also show that rapid thermal annealing produces much thinner interface-reacted layers than does the conventional (resistive) heat treatment.20332833

High-resolution synchrotron radiation Renninger scan to examine hybrid reflections in InGaP/GaAs(001)

High-resolution synchrotron radiation Renninger scans (RS) have been used in the analysis of hybrid reflections in the InGaP/GaAs structure. Four-beam cases involving two Bragg (primary and secondary) and one Laue (secondary) reflections of the 002 Renninger scans for the GaAs substrate and the InGaP layer were analysed in detail. Different structures of asymmetry regarding the inplane directions [110] and [1] were observed from the measurements of the same three families of four-beam cases, {1} /{1 1}3, {20}0/{20}2 and {3 } /{3 }3, at phi several positions. The comparison between the experimental and MULTX simulated scan clearly shows a marked asymmetry observed on the {20}0/{20}2 contributions. An asymmetric peak instead of the simulated dip appears due to the layer Laue secondary beam {20}0 crossing the layer/substrate interface to generate a hybrid peak. The break in the lattice coherence for this heterostructure is shown by the occurrence of an unexpected dip in the layer RS, which does not obey the mirror symmetry.61293