Imaging of Arsenic Cottrell Atmospheres Around Silicon Defects by Three-Dimensional Atom Probe Tomography

Abstract

Discrete control of individual dopant or impurity atoms is critical to the electrical characteristics and fabrication of silicon nanodevices. The unavoidable introduction of defects into silicon during the implantation process may prevent the uniform distribution of dopant atoms. Cottrell atmospheres are one such nonuniformity and occur when interstitial atoms interact with dislocations, pinning the dislocation and trapping the interstitial. Atom probe tomography has been used to quantify the location and elemental identity of the atoms proximate to defects in silicon. We found that Cottrell atmospheres of arsenic atoms form around defects after ion implantation and annealing. Furthermore, these atmospheres persist in surrounding dislocation loops even after considerable thermal treatment. If not properly accommodated, these atmospheres create dopant fluctuations that ultimately limit the scalability of silicon devices.

Order–disorder transition in a two-dimensional boron–carbon–nitride alloy

“…1c-f). The fact that these mortar threads are composed of carbon can be judged from its decreased coverage on the surface upon B/N enrichment, and increased coverage after carbon enrichment at 900 K. The occurrence of the brick-andmortar structure observed here describes the classic segregation of solute at sinks such as grain boundary, dislocation and free surface, which is analogous to the so-called Cottrell atmospheres created by clouds of impurity atoms near dislocations in crystals 20 . The segregation sites aligning with the centre of moiré humps are the most accessible and energetically favourable sink for carbon segregants.…”

Atom probe tomography in nanoelectronics

“…Distribution of boron or Pt in NiSi silicides used in contacts of transistors [2,3], clustering of boron in heavily implanted silicon [4,5], Cottrell atmospheres in arsenic-implanted silicon [6] were recently investigated demonstrating the nearly atomic-scale resolution and a e-mail: didier.blavette@univ-rouen.fr quantitativity of APT for semi-conductors [7,8]. Besides, the characteristic size of latest generation nanotransistors, that is basically two times a technological node (∼50 nm) is now below the APT field of view (∼100 × 100 nm 2 ) so that 3D reconstruction of the distribution of the device and of dopants is now achievable.…”

The investigation of boron-doped silicon using atom probe tomography

“…The SIMS occupies a central position in microelectronics for dopant profiling in semiconductors. However, for nano-transistors SIMS faces to its ultimate limits and 3DAP is appealed on to play an important role [8]. Moore's law will soon experience new physical limits and new challenges for which the LaWaTAP could bring new and relevant results.…”