Non-destructive techniques applied to the detection of oxygen or metallic precipitates in annealed Cz silicon wafers

Non-destructive techniques such as scanning infrared microscopy (SIRM), Fourier transform infrared spectroscopy (FTIR), light-beam-induced current (LBIC) mapping and diffusion length (L(n)) measurement techniques, associated with chemical etching were used to detect precipitates in annealed Czochralski (Ct) silicon wafers and to control their interaction with self-interstitials injected into the bulk by phosphorus diffusion or by oxidation. The effect of metallic contamination was also studied by copper diffusion. After nucleation (750 degrees C) and/or growth (900 degrees C) annealings phosphorus diffusion at 900 degrees C for 4 h shrinks the precipitates revealed by SIRM. This shrinkage is due to a marked injection of self-interstitials in the bulk. Annealing of the two-step annealed samples in oxygen produces a similar effect. However, new defects are detected by SIRM, defects which are identified as stacking faults.