Influence of the surface Si/buried oxide interface on extended defect evolution in silicon-on-insulator scaled to 300 Å

Abstract

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.

Kinetics of {311} defect dissolution in silicon-on-insulator (SOI)

“…1-4 agree with previous studies of dislocation loop and {3 1 1} evolution in SOI [10,11]. As the implant energy increases, or the surface silicon thickness Table 4 Extracted activation energies from Fig.…”

“…5 decreases, it becomes easier for interstitials to recombine at the surface Si/BOX interface. It has been hypothesized that damage to the interface strongly affects the ability of interstitials to recombine [10]. Thus, as the implant energy increases more of the incident ions reach the BOX increasing the damage to the interface.…”

“…This phenomenon is likely to be critical as SOI devices are scaled. Previous studies have shown that dislocation loop [10] and {3 1 1} [11] nucleation can depend strongly on the SOI thickness and/or implant energy. The present study set out to investigate the reaction kinetics of {3 1 1} defect dissolution in SOI, and then compare it to bulk silicon.…”

Evolution of end-of-range defects in silicon-on-insulator substrates

“…It is commonly accepted [2,3,[5][6][7] that the density and size of EOR defects decreases when passing from Bulk Silicon to SOI but different arguments are used in the literature to explain this reduction. The possible effect of the Si top layer/BOX interface acting as a sink, for example, has been confirmed by some already published experimental analysis [2,5], and ruled out by others [3,7].…”

“…The presence of the BOX can alter the interstitial concentration in the Si top layer in two ways: by reducing the initial concentration of interstitial created by the implant [2,3] or acting as a sink for interstitial recombination [4,5].…”