Interstitial defects in silicon from 1–5 keV Si+ ion implantation

Abstract

Extended defects from 5-, 2-, and 1-keV Si+ ion implantation are investigated by transmission electron microscopy using implantation doses of 1 and 3×1014 cm−2 and annealing temperatures from 750 to 900 °C. Despite the proximity of the surface, {311}-type defects are observed even for 1 keV. Samples with a peak concentration of excess interstitials exceeding ∼1% of the atomic density also contain some {311} defects which are corrugated across their width. These so-called zig-zag {311} defects are more stable than the ordinary {311} defects, having a dissolution rate at 750 °C which is ten times smaller. Due to their enhanced stability, the zig-zag {311} defects grow to lengths that are many times longer than their distance from the surface. It is proposed that zig-zag {311} defects form during the early stages of annealing by coalescence the high volume density of {311} defects confined within a very narrow implanted layer. These findings indicate that defect formation and dissolution will continue to control the interstitial supersaturation from ion implantation down to very low energies.

Nonconservative Ostwald ripening of dislocation loops in silicon

“…Our experimental results are in qualitative agreement with previous data on dislocation loop annealing in ion implanted Si ͑Refs. 3, 6, 22, and 23͒ as well as with experiments 13,14,25,26 and modeling 4 showing a depth dependent duration of TED of B in Si. In the experimental investigations reported in Refs.…”

“…8-10, 17, 20, and 21 while the experiments reported in Refs. 3, 6, 16, and 22-24 are in favor of nonconservative Ostwald ripening models as well as the observed dependence of TED on the projected range of the implanted ions 4,13,14,25,26 which can be identified with the location depth of ͕311͖ defects. Hence, conclusive experiments are needed to settle this apparent discrepancy.…”

Growth and shape transition of small silicon self-interstitial clusters

“…The formation and structure of rodlike ͕311͖ defects have been well characterized by high-resolution transmission electron microscopy ͑HRTEM͒. [3][4][5] In addition, a series of recent spectroscopy measurements [6][7][8][9][10][11] have evidenced existence of small compact self-interstitial clusters before they evolve into larger extended defects. In ultrashallow junction formation with low-energy implanted dopants, such small interstitial clusters are thought to be a main source for free interstitials responsible for dopant transient enhanced diffusion and agglomeration during postimplantation thermal treatment.…”

Simulation of Defects and Diffusion Phenomena in Silicon

“…Figure 5 shows the concentration of interstitials contained in {311} defects along with experimental data of Moller, 23 Agarwal, 24 Lilak, 25 and Eaglesham. During the damage anneal, the excess interstitials and vacancies create an enhancement of the diffusivity that can be quite dramatic.…”