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We developed a new UV-Raman spectroscopy system for local and global strain measurements in Si. Using a 364 nm excitation laser, strain in an ultra-thin Si film can be measured. Because of the resonance effect using this particular wave length, reasonably short measurement time is realized to obtain strain mapping with keeping the sample at sufficiently low temperature. An in situ wavenumber calibration system has been newly developed for superior wavenumber resolution and precision of approximately 0.1 cm À1 . A quasi-line shape excitation light source has also been developed to verify the effective spatial resolution. Strain mapping and spectral measurements for relaxation by rapid thermal annealing in strained-Si substrates are demonstrated.

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The structures and coalescence behavior of size-selected, matrix-isolated silicon clusters have been studied using surface-plasmon-polariton ͑SPP͒ enhanced Raman spectroscopy. The cluster ions were produced in a laser vaporization source, mass selected then deposited into a co-condensed matrix of Ar, Kr or N 2 on a liquid He cooled substrate. Raman spectra from monodisperse samples of the smaller clusters studied, Si 4 , Si 6 and Si 7 , show sharp, well-resolved, vibrations which are in good agreement with predictions based on ab initio calculations. From these comparisons we confirm that Si 4 is a planar rhombus, and assign Si 6 as a distorted octahedron and Si 7 as a pentagonal bypyramid. Si 5 depositions down to 5 eV did not reveal a measurable Raman spectrum under our experimental conditions. Evidence for cluster-cluster aggregation ͑or fragmentation͒ was observed under some conditions, even for a ''magic number'' cluster such as Si 6 . The spectra of the aggregated small clusters were identical to those observed for directly deposited larger cluster ''bands,'' such as Si [25][26][27][28][29][30][31][32][33][34][35] . The Raman spectra of the aggregated clusters bear some similarity to those of bulk amorphous silicon. Cluster-deposited thin films were prepared by sublimating the matrix material. Even under these ''soft landing'' conditions, changes in the Raman spectrum are observed with the thin films showing even greater similarity to amorphous silicon.