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Reactive ion beam etching of InP with chlorine gas under oblique angles of incidence is reported. This process offers the important advantage of edge profile control. The etch rate is strongly dependent upon the ion energy, manifesting a plateau approaching 0.2 μm/min for a chlorine beam of less than 1 keV. At normal incidence of the ion beam the walls are sloped outward by about 17°. A mesa-type structure with straight, smooth vertical walls has been fabricated by spinning the substrate under oblique ion beam incidence.

The pure rotational Raman spectrum of 19F2 has been recorded photographically with a reciprocal linear dispersion of 1.4 cm-' mm-I and analysed to yield ; Bo = 0.883 31 +O.O00 04 cm-* ; 106Do = 3.48 -t 0.06 cm-I ; ro = 1.417 44+ 0.000 06 A. Assuming from earlier work, B1 = 0.872 5 0,002 cm-', the following equilibrium constants were obtained ; Be = 0.889+ 0.001 cm-I ; re = 1.413 1 + 0.000 8 A.These are the most precise values yet reported for Bo, Do and yo, re of I9Fz. The experimentally determined Do value is in good agreement with the value calculated from Bo and w o .

Nanoindentation was used to measure the mechanical properties of 200mm diameter (100) CZ Si wafers subjected to the initiation and propagation of micro-crack defects. Silicon amorphization and phase changes were observed and accompanied by a monotonic decrease in hardness and elastic modulus, as the nanoindent tip approached the micro-crack shank or point. Identification and profiling of these localized phase transitions was obtained in the vicinity of the micro-cracks using electron back-scattered diffraction (EBSD) and Raman spectroscopy. It was found that the amorphous Si regions extend for about 10 µm at the edges and ahead of a moving crack tip. Wafers from ingots grown at faster growth rates with enhanced thermal gradients and associated point defect/impurity produce large localized stresses in the wafer core, which are capable of changing the path of propagating cracks. FTIR and Raman spectroscopy analysis were used to quantify local stresses due to radial oxygen precipitate variations. The resulting stress modified crack deviates considerably from energetically favorable [110]/(111) directions, following a radial path suggesting a ductile fracture failure mode.