Raman spectroscopy was used for analysis of phase transformations and residual stress in machined silicon. Wear debris from dicing of silicon was scanned with a Raman spectrometer. Recorded spectra manifest the presence of amorphous Si, hexagonal phase (Si-IV), bc8 phase (Si-III) and pristine Si-I under residual stress. On surfaces of diced wafers as well as lapped silicon wafers, the r8 phase (Si-XII) was detected in addition to the above phases. The composition of phases in diced cross sections of silicon wafers differs dramatically between high and low speed cuts. The quantification of these phases was attempted by curve fitting each spectrum with corresponding peaks of each phase. Subsequently, relative intensity maps of specific phases were generated. Thus, Raman spectroscopy studies of machined surfaces demonstrated metallization of Si under a variety of machining conditions including lapping, grinding, scratching, dicing and slicing. All metastable phases of silicon disappear after etching and polishing of respective wafers. No evidence of phase transformations was found on a quartz-damaged silicon wafer surface. Residual stress having a characteristic distribution was observed in this case.

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Internal gettering efficiencies and stabilities of high and low carbon doped silicon have been compared with standard and ramped annealing conditions. The gettering efficiency of low carbon silicon has been found to be greatly enhanced with ramped annealing by creating a high concentration of oxygen precipitates and related defects. This ramped low carbon material and both the standard and ramped high carbon materials have a greatly enhanced oxygen precipitation rate, relative to the standard low carbon standard anneal. However, the high carbon material’s gettering efficiency and stability are low, compared to the ramped low carbon material, due to a reduction of the oxygen precipitate’s strain field and concentration of related defects.

Results of IR spectroscopic as well HVTEM investigations are given on the precipitation of oxygen in Si due to heat treatment within the temperature range 600 to 1275 °C. The initial oxygen concentrations of the Si samples are about 9 × 1017 cm−3 and about 1.5 × 1018 cm−3, respectively, with different concentrations of carbon within the range 1016 cm−3 ≦ [Cs]0 ≦ 1 × 1017 cm−3 in each case. It is shown that four different kinds of Si‐oxygen precipitates exist at least, in dependence on the temperature of heat treatment. [Oi]0, [Cs]0, and the thermal history of the samples heat treated. It is assumed that there is only heterogeneous nucleation within the whole temperature range. For temperatures T ≧ 900 °C the oxygen precipitation occurs by the growth of asgrown microprecipitates. The origin of various IR spectra and corresponding HVTEM microphotographs is interpreted as being caused by differences in the shape and size of the Si‐oxygen‐precipitates.

Surface photovoltage ͑SPV͒ measurements are traditionally carried out under steady-state conditions to determine the minority carrier diffusion length. While this technique is very convenient for bulk wafer defect characterization, especially the detection of iron in boron-doped silicon wafers, it is poorly suited to characterize epitaxial layers that are typically much thinner than the minority carrier diffusion length. We have developed the theory for frequency-dependent SPV measurements and have verified this theory with experimental data. We consider the various recombination/generation components in the semiconductor and determine the dependence on photon flux density, optical absorption coefficient, doping density, recombination lifetime, and temperature. Epitaxial layers are usually measured with techniques that are sensitive to generation parameters confined to the reverse-biased space-charge region ͑scr͒. We show that optical excitation can be used for scr confined recombination measurements, but the resultant lifetime is an effective lifetime incorporating both scr and surface recombination, heavily influenced by surface recombination.