Damage accumulation in neon implanted silicon

Abstract

Damage accumulation in neon-implanted silicon with fluences ranging from 5 ϫ 10 14 to 5 ϫ 10 16 Ne cm −2 has been studied in detail. As-implanted and annealed samples were investigated by Rutherford backscattering spectrometry under channeling conditions and by transmission electron microscopy in order to quantify and characterize the lattice damage. Wavelength dispersive spectrometry was used to obtain the relative neon content stored in the matrix. Implantation at room temperature leads to the amorphization of the silicon while a high density of nanosized bubbles is observed all along the ion distribution, forming a uniform and continuous layer for implantation temperatures higher than 250°C. Clusters of interstitial defects are also present in the deeper part of the layer corresponding to the end of range of ions. After annealing, the samples implanted at temperatures below 250°C present a polycrystalline structure with blisters at the surface while in the other samples coarsening of bubbles occurs and nanocavities are formed together with extended defects identified as ͕311͖ defects. The results are discussed in comparison to the case of helium-implanted silicon and in the light of radiation-enhanced diffusion.

Long-Range Electron Interferences at a Metal Surface Induced by Buried Nanocavities

“…After annealing at 1075 K for 20 min the argon peaks vanish. Although not specifically tested in great detail, similar processes should take place when implanting Ne [13]. This shows that thermal treatments allow us to control size and density of the subsurface nanocavities formed by different gases.…”

Helium implanted gallium nitride evidence of gas-filled rod-shaped cavity formation along the c-axis

“…This is in agreement with recent results on Neimplanted Si, which suggest that the presence of Ne in bubbles slows down both the growth and the faceting of bubbles. 31 The role of the impurities is, however, not clear; oxygen, for example, can impede the faceting of the He bubbles in Si ͑Ref. 35͒ whereas it is invoked in the formation of pyramidal voids 3 during the GaN growth.…”

“…5 A similar mechanism is observed in implanted Si at elevated temperature where ͕311͖ defects are observed beyond the bubble layer. 14,31 These DLs could also result from the loop punching phenomenon. In this case, gasfilled cavities ͑referenced as bubbles͒ in an overpressurized state can relieve their increasing pressure when the He accumulates during implantation, by punching out interstitial loops.…”

Lithium implantation at low temperature in silicon for sharp buried amorphous layer formation and defect engineering

“…extended defects. 10 Figure 5 shows a cross-sectional TEM image of silicon sample obtained after implantation with neon at 50 keV, 250 C followed by annealing at 800 C for 30 min. Bubbles are forming a 250 nm wide layer starting at the implanted surface.…”

“…As observed for Fe, 24 Ne, 10 or He, 27 Li atoms present in the amorphous layer must be swept by the recrystallization front. This leads to a high concentration of Li in the middle.…”