Abstract
Defects in highly nitrogen-doped 4H-SiC deformed by cantilever bending at 550°C have been identified by weak-beam and high-resolution transmission electron microscopy techniques. The induced-defects consist of double stacking faults (DSFs) whose expansion produces a local 4H → 3C phase transformation. Each DSF is bound by two identical 30° Si(g) partial dislocations which glide on two adjacent basal planes. The DSFs belong to three different populations which differ by their extension as a function of the applied-stress and the 30° Si(g) characteristics (line direction L , Burgers vector b , glide planes and glide direction). The external mechanical stresses are the main driving forces involved in the DSF expansion. However, extra driving forces such as thermodynamic or electronic forces are also likely to be involved.
Acknowledgements
The present authors gratefully thank the team of the Centre Pluridisciplinaire et de Microscopie Electronique et de Microanalyse, Université Paul Cézanne, where both FIB experiments and HRTEM observations were performed and ONERA, Châtillon, for the use of conventional JEOL 200CX for WB studies.
Notes
Present address: Centre d’Elaboration des Matérianx et d’ Etudes Structurales, Unité Propre de Recherche associée an CNRS 8011, 29 rue Jeanne Marvig, BP 94347, 31055 Toulouse Cedex 4, France.