The fabrication of ultrathin strained silicon directly on insulator is demonstrated and the thermal stability of these films is investigated. Ultrathin (∼13 nm) strained silicon on insulator layers were fabricated by epitaxial growth of strained silicon on relaxed SiGe, wafer bonding, and an etch-back technique employing two etch-stop layers for improved across wafer thickness uniformity. Using 325 nm Raman spectroscopy, no strain relaxation is observed following rapid thermal annealing of these layers to temperatures as high as 950 °C. The thermal stability of these films is promising for the future fabrication of enhanced performance strained Si ultrathin body and double-gate metal-oxide-semiconductor field-effect transistors.

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A bond and etch back technique for the fabrication of 13-nm-thick, strained silicon directly on insulator has been developed. The use of a double etch stop allows the transfer of a thin strained silicon layer with across-wafer thickness uniformity comparable to the as-grown epitaxial layers. Surface roughness of less than 1 nm was achieved. Raman analysis confirms strain remains in the thin silicon layers after the removal of the SiGe that induced the strain. Ultra-thin strained silicon-on-insulator (SSOI) substrates are promising for the fabrication of ultra-thin body and double-gate, strained Si metal-oxide semiconductor field-effect transistors (MOSFETs).

A technique that uses quantitative electron diffraction contrast imaging (EDCI) to measure stress with a spatial resolution on the order of 10nm and sensitivity on the order of tens of MPa is applied to strained-Si metal-oxide-semiconductor field-effect transistors. This is accomplished by utilizing transmission electron microscopy and focused ion beam micromachining in conjunction with finite element modeling and electron diffraction contrast simulations. Our techniques enable quantitative interpretation of EDCI intensity, as a function of the magnitude of the local stress field. Analysis shows that the stress distribution in the strained-Si channel is very sensitive to the stress state of the surrounding materials, especially TiSi2, which can modify the stress distribution in the channel by well over 100MPa.

We have employed high resolution angle resolved photoemission spectroscopy (ARPES) measurements to investigate many-body renormalizations of the single-particle excitations in 1T -TiSe2 . The energy distribution curves of the ARPES data reveal intrinsic peak-dip-hump feature, while the electronic dispersion derived from the momentum distribution curves of the data highlights, for the first time, multiple kink structures. These are canonical signatures of a coupling between the electronic degrees of freedom and some Bosonic mode in the system. We demonstrate this using a model calculation of the single-particle spectral function at the presence of an electron-Boson coupling. From the self-energy analysis of our ARPES data, we discern some of the critical energy scales of the involved Bosonic mode, which are ∼15 and 26 meV. Based on a comparison between these energies and the characteristic energy scales of our Raman scattering data, we identify these Bosonic modes as Raman active breathing (A1g) and shear (Eg) modes, respectively. Direct observation of the band-renormalization due to electron-phonon coupling increases the possibility that electron-phonon interactions are central to the collective quantum states such as Charge density wave (CDW) and superconductivity in the compounds based on 1T -TiSe2 .