Crack interactions in tensile-strained epilayers

摘要

When epilayers are grown under tensile strain cracks are formed where the critical thickness, t_c, is exceeded. At thicknesses less than about 4t_c these form a unidirectional array on (110) planes but at a thickness of greater than 6t_c an orthagonal (110) array is introduced. By analysis of the intercrack spacing in (110) gratings a high degree of self ordering is demonstrated. When orthogonal cracks interact three outcomes have been identified, namely "T" junctions, straight intersections and jogs, and it is shown that these are in response to the relative depth of the two cracks at the junctions.