Metal Decorated Defects in Heat‐Treated Silicon Wafers

Using transmission electron microscopy combined with energy dispersive x‐ray spectrometry we have analyzed the structure of haze microdefects. Mechanical contact with stainless steel or kovar followed by oxidation at 1100°C produced extrinsic stacking faults decorated with Ni. Fe, Cr, and Co were found only at the wafer surface where contact was made. Noncontaminated wafers were found to contain similar defects at lower densities, which were decorated with Cu. A mechanism of formation is proposed which involves the dissolution, diffusion, and precipitation of the metal impurities. Cu and Ni are believed to be more effective in this process due to their high interstitial solubilities.