Defect structure of EFG silicon ribbon

Abstract

The defect structure of EFG ribbons has been studied using EBIC, TEM and HVEM. By imaging the same areas in EBIC and HVEM a direct correlation between the crystallographic nature of defects and their electrical properties has been obtained. Partial dislocations at coherent twin boundaries may or may not be electrically active. Since no microprecipitates were observed at these dislocations it is likely that the different electrical activity is a consequence of the different dislocation core structures. Second order twin joins were observed which followed the same direction as the coherent first order twins normally associated with EFG ribbons. These second order twin joins are in all cases stronly electrically active. EFG ribbons contain high concentrations of carbon. Since no evidence of precipitation was found with TEM it is suggested that the carbon may incorporated into the higher order twin boundaries now known to exist in EFG ribbons.