TEM CHARACTERIZATION OF DEFECT CONFIGURATIONS IN SUBMICRON SOI STRUCTURES

Transmission electron microscopy has been used to investigate the origin and propagation of defects in novel submicron SOI structures. Defect configurations observed in the structures could be explained in terms of dislocations generated as a result of stresses induced during the fabrication sequence. Dislocations were found to originate at the silicon/oxide interface and then propagate into the silicon along particular {111} glide planes. Defect densities were observed to depend on the geometry of the structures. The observations are in agreement with the concept of critical stress levels for incorporation of defects being exceeded in particular structures; stress levels depend on the dimensions of the geometry. Completely isolated island-structures can be obtained virtually free of defects; islands which are connected to the substrate can also be obtained virtually defect-free.