As device dimensions continue to be scaled, incorporation of silicon-on-insulator ͑SOI͒ as mainstream complementary metal-oxide-semiconductor technology also increases. This experiment set out to further investigate the effect of the surface Si/buried oxide ͑BOX͒ interface on the formation and dissolution of extended defects in SOI. UNIBOND® wafers were thinned to 300, 700, and 1600 Å. Si ϩ ion implantation was performed from 5 to 40 keV with a constant, nonamorphizing dose of 2ϫ10 14 cm Ϫ2 . Inert ambient furnace anneals were performed at 750°C for times of 5 min up to 8 h. Transmission electron microscopy was used to study the evolution of extended defects, as well as to quantify the number of trapped interstitials. It is observed that the surface Si/BOX interface does not enhance the dissolution rate of extended defects unless у15% of the dose is truncated by the BOX. Further, no reduction in the trapped interstitial concentration is seen unless у6% of the dose is truncated. It is concluded that the surface Si/BOX interface does not serve as a significant sink for interstitial recombination, as long as the interstitial profile is mostly confined to the surface Si layer.

Silicon-on-insulator (SOI) is a promising alternative to bulk silicon as ultra shallow junction depths have begun to shrink below 50 nm. This study examined the effect of the SOI surface silicon/buried oxide interface on {311} defect evolution after Si+ ion implantation. SOI wafers were produced such that the surface silicon thickness varied from 300Å to 1600Å. Non-amorphizing Si+ implants at 5 and 20 keV with a dose of 2x1014 cm-2 were performed into SOITEC SOI wafers. Furnace anneals were done at 750°C from 5 minutes to 4 hours and quantitative transmission electron microscopy (QTEM) was used to study the implant damage evolution. At 5 keV, the dissolution behavior of the SOI was very similar to that of the bulk. However, the extended defects in the 300 Å SOI did not nucleate the same as those observed in the bulk or thicker SOI. Similar results were seen at 20 keV for the 700 Å SOI, but a slight decrease in the concentration of trapped interstitials was observed due to interface recombination as a result of the increased projected range of the implant. It is concluded that the surface Si/BOX interface does not significantly affect recombination of interstitials trapped in extended defects unless the interstitial profile is close to or truncates the interface. However, the interface does appear to affect the stability of zig-zag {311} defects and dislocation loops in thin SOI at lower implant energies.

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Molecular beam epitaxial Si1-xGex layers of various Ge concentrations ranging from 0% to 50% were grown on top of a Si substrate. The wafers were then implanted with a 40 keV, 1 x 1014cm-2 Si+. To study the development of {311} defects, the samples were annealed at 750°C for times ranging from 0 to 20 minutes. TEM was utilized to observe both the formation and dissolution of the defects. The Si1-xGex samples with ≤ 5% Ge exhibit {311} defect formation and dissolution; however, samples with the Ge content lying between 15% and 50% showed only dislocation loop formation. It is suggested that the decrease in bond strength with increasing Ge content is the reason for the lack of {311} defect formation.