A study of the growth and shrinkage of stacking faults in SIMOX

This paper presents the results of a study of the behaviour of stacking faults (SFs) resulting from specific sacrificial oxidation of separation by implanted oxygen (SIMOX) material in dry O2. This oxidation was chosen because growth of large SFs take place and these can be easily observed using a two-step selective etch process. A four-step etch process was used for dislocations and SFs in thin overlayers. A newly developed automatic counting system was used to determine the size and density of defects. Measurements were conducted on samples with top layer silicon thickness in the range 300–1600 Å, as this includes thin layers suitable for fully depleted complementary metal oxide semiconductor devices. The activation energy for growth of SFs in dry O2 was found to be 2.5 eV, in good agreement with published values for bulk silicon. For shrinkage in an Ar ambient the activation energy was determined to be 4.6 eV, again in good agreement with published values for bulk silicon. The activation energy was found to remain constant over the range 600–1600 Å. However, for samples in the range 300–500 Å no shrinkage took place following the annealing processes used in this study. From these results it can be concluded that in the range 600–1600 Å the mechanisms for shrinkage of SFs are the same in SIMOX as in bulk silicon.