Characterization of Precipitates Decorating Stacking Faults in Single Crystal Silicon

Abstract

ABSTRACTOxidation of silicon wafers containing lattice damage at the surface normally results in the formation of extrinsic stacking faults. Optical microscope investigation following decorative etching shows that on certain samples the faults have a straight line appearance while on others the ends of the defect are much enlarged giving a “dog-bone” shape. TEM investigation confirmed that the dog-bone shaped faults were decorated with colonies of precipitates near their edges. These colonies resided on the (111) fault planes and extended over several thousand angstroms. Precipitate spots were not found in the diffraction pattern due to the small volume fraction, but translational Moire fringes were observed for certain matrix g-vectors, thus aiding in the crystallographic analysis. EDX analysis was also performed and revealed that precipitates were due to Cu and Ni contamination. The electrical impact of the defects on P-N junction was measured, showing a strong influence on both reverse and forward bias current/ voltage characteristics.