Measurements of Dislocation Locking by Near-Surface Ion-Implanted Nitrogen in Czochralski Silicon

Journal article

A modified dislocation unlocking technique is used to measure dislocation locking due to nitrogen implanted into Czochralski silicon. The results show that near-surface dislocations can be locked by implanted nitrogen. The magnitude of the locking measured suggests that nitrogen transport proceeds by a dissociative mechanism, where transport occurs by the splitting of immobile dimers into fast monomers, rather than movement of nitrogen dimers. In other experiments, nitrogen-doped float-zone silicon is investigated using the standard dislocation unlocking technique. The results give an activation energy for effective nitrogen diffusion in silicon of 3.24±0.25 eV at 500-750°C. Using the assumption that the dislocation locking strength per nitrogen atom is the same as that of oxygen, a value of 200,000 cm2 s-1 can be inferred for the effective diffusivity prefactor. If analyzed using the dissociative model, an activation energy of 1.1-1.4 eV is found for nitrogen monomer diffusion, with a diffusivity prefactor of 30 cm2 s-1. © 2009 The Electrochemical Society.

Authors: Alpass, C; Jain, A; Murphy, J; Wilshaw, P

• Publication status: Published
• Journal: JOURNAL OF THE ELECTROCHEMICAL SOCIETY
• Volume: 156
• Issue: 8
• Pages: H669-H673
• Publication date: 2009-01-01
• DOI: 10.1149/1.3151813
• ISSN: 0013-4651
• Language: English
• Keywords: nitrogen; silicon; dislocation locking; elemental semiconductors; dissociation; ion implantation; diffusion