Si Surface Roughness Research Articles

GROWTH AND CHARACTERIZATION OF EPITAXIAL Si/CoSi2 AND Si/CoSi2/Si HETEROSTRUCTURES

AbstractThin (<200Å), epitaxial CoSi2 films have been grown on (111) Siwafers in a UHV system using a variety of growth techniques including solid phase epitaxy (SPE), reactive deposition epitaxy (RDE), and molecular beam epitaxy (MBE). SEN and TEN studies reveal significant variations in the epitaxial silicide surface morphology as a function of the sillciqd formation method. Pinhole densities are generally greater than 107 cm-2, although some reduction can be achieved by utilizing proper growth techniques. Si epilayers were deposited over the CoSi2 films inthe temperature range from 550ºC to 800ºC, and the reesuulttinng structures have been characterized using SEM, cross—sectional TEN, and ion channeling measurements. These measurements show that the Si epitaxial quality increases with growth temperature, although the average Si surface roughness and the CoSi2 pinhole density also increase as the growth temperature is raised.

Optical Microanalysis of Small Semiconductor Structures

ABSTRACTRaman spectroscopy is a powerful tool for evaluating semiconductor crystal characteristics with a diffraction–limited spatial resolution of approximately 0.5 μm, comparable to device structure dimensions. Examples are presented of the use of Raman scattering to measure stress variations across Sion-insulator and Si-on-sapphire stripes with dimensions down to 2 μm and, to probe the spatial variation in the effectiveness of annealing of a Si layer deposited over metal device structures. Detailed measurements of the variation in the Raman spectra of thin crystalline Si films, with thicknesses down to 3.0 nm, are discussed. Measurements made on roughened Si surfaces are presented which show that surface morphology on a submicron spatial scale results in enhanced Raman intensities.

Polarimetry of Specular and Non-Multiple-Scattered Electromagnetic Radiation from Selectively Roughened Si Surfaces

We show by application to Si that polarimetric measurements on radiation reflected nonspecularly from rough surfaces can distinguish between geometric-optics (facet or tangent-plane) and Rayleigh-Fano (random diffraction grating) scattering models, thus providing new details about surface roughness. A class of macroscopically rough but microscopically smooth surfaces is found that gives accurate specular ellipsometric data while being unsuitable for reflectance measurements.