Depth profiling of vacancy clusters in MeV-implanted Si using Au labeling

Abstract

A technique for profiling the clustered-vacancy region produced by high-energy ion implantation into silicon is described and tested. This technique takes advantage of the fact that metal impurities, such as Au, are trapped in the region of excess vacancies produced by MeV Si implants into silicon. In this work, the clustered-vacancy regions produced by 1-, 2-, and 8-MeV Si implants into silicon have been labeled with Au diffused in from the front surface at 750 °C. The trapped Au was profiled with Rutherford backscattering spectrometry. The dynamics of the clustered-vacancy region were monitored for isochronal annealing at 750–1000 °C, and for isothermal annealing at 950 °C, for 10–600 s. Cross-sectional transmission electron microscopy analysis revealed that after the drive-in anneal, the Au in the region of vacancy clusters is in the form of precipitates. The results demonstrate that the Au-labeling technique offers a convenient and potentially quantitative tool for depth profiling vacancies in clusters.

Evolution of fluorine and boron profiles during annealing in crystalline Si

“…8 In our case, a fraction of F implanted dose is retained around two well-defined peaks, one near the surface and the other one around R p . The gettering of impurities in these zones has been reported before 13 and it has been associated with regions with excess Vs and Si Is, respectively. Due to the momentum transfer of the incoming ion, there is a net spatial separation of point defects in the generated cascade: empty lattice sites ͑Vs͒ are predominant close to the surface while excess Si Is are placed slightly deeper than R p .…”

Gettering of copper in silicon at half of the projected ion range induced by helium implantation

“…According to binary collision calculations, 5,6,26,27 excess vacancies are formed because of the spatial separation of point defects due to the nonzero momentum component of the displaced Si atoms into the beam direction. In fact, the assumption of a complete local vacancy-interstitial annihilation during annealing leads to: ͑i͒ the formation of a vacancy-rich layer from the surface nearly up to R p and ͑ii͒ the formation of an interstitial-rich region slightly extended beyond the R p depth ͑with the maximum concentration of excess interstitials at about 1.2 R p ͒.…”

“…The vacancy-rich region arises because of the slight displacement between the vacancy and interstitial generated in a high-energy knock on, as suggested by atomistic simulations. 5,6 The assumption of complete local point defect recombination ͑after the annealing͒ leads to a local vacancy excess at the near-surface region and an interstitial excess towards the R P of the implant. The existence of defects at R P /2 can be verified experimentally in most cases only by means of the impurity decoration method.…”

“…Oxygen as well as the transition metals are very efficiently trapped in the R P /2 region. [5][6][7] The supersaturation of vacancies can be monitored by the transient enhanced diffusion ͑TED͒ of Sb spikes. On the other hand, the TED of B in the same region indicates supersaturation of self-interstitials there.…”

The Interaction of Hydrogen with Deep Level Defects in Silicon

“…Very recently, Au 'labelling' has been used to map the concentration of vacancy clusters in MeV-implanted Si [198].…”