The interface structure of wafer fused InP to Silicon at 220 deg C was investigated by high-resolution transmission electron microscopy (TEM) and micro-Raman spectroscopy. TEM measurements reveal the ...formation of a thin amorphous layer with the presence of a few nanocrystallites at the interface. Cross-sectional Raman scattering measurements carried out on the cleaved interface regions show a clear evidence of nanocrystalline silicon fractions within the nonstoichiometric silicon oxides. Because micro-Raman probing is sensitive to atomic scale disorder and crystallite size, Raman line shape analysis has also been explored to confirm the formation of nanocrystalline silicon (nc-Si) at the bonded interface.
The nuclei below lead but with more than 126 neutrons are crucial to an understanding of the astrophysical \(r\)-process in producing nuclei heavier than \(A\sim190\). Despite their importance, the ...structure and properties of these nuclei remain experimentally untested as they are difficult to produce in nuclear reactions with stable beams. In a first exploration of the shell structure of this region, neutron excitations in \(^{207}\)Hg have been probed using the neutron-adding (\(d\),\(p\)) reaction in inverse kinematics. The radioactive beam of \(^{206}\)Hg was delivered to the new ISOLDE Solenoidal Spectrometer at an energy above the Coulomb barrier. The spectroscopy of \(^{207}\)Hg marks a first step in improving our understanding of the relevant structural properties of nuclei involved in a key part of the path of the \(r\)-process.
A low temperature direct wafer bonding of semiconductor substrates has been envisaged. The method developed overcomes the previous techniques where high temperature is required for direct bonding. A ...combination of specific chemical cleaning and plasma treatment enables the wafers to be adhered together at room temperature. Heat treatment at around 220/spl deg/ C with pressure enables the wafers to be atomically bonded. TEM micrograph reveals that the bonded interface is uniform and smooth. In addition micro-Raman (MR) and SEM with EDAX were also used to investigate the bonded interface. Electrical measurements reveal that the interface does not obstruct the passage of current. This technique would be useful to fabricate photonic devices and also extended for packaging applications.
We report fabrication processes to realize freestanding GaN micromechanical structures on silicon-on-insulator (SOI) substrates. GaN layers were grown on (100) SOI substrates by metallorganic ...chemical vapor deposition. Prior to GaN growth, the surface of thin SOI overlayer was subjected to KOH treatment to expose {111} lattice planes. High-resolution X-ray diffraction, photoluminescence, and micro-Raman measurements were used to characterize these wurtzite GaN films. Using the combination of dry and wet etching techniques for surface micromachining, we have succeeded in releasing freestanding GaN structures on SOI platform. Such an approach is suitable for the fabrication of GaN-based microelectromechanical systems.
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