The Identification, Annihilation, and Suppression Nucleation Sites Responsible for Silicon Epitaxial Stacking Faults

A study of the formation of epitaxial stacking faults in 2 in. diameter, dis-location-free (111) silicon wafers used in the fabrication of standard buried collector transistors has been made. The nucleation sites for the epitaxial faults are introduced uring the initial oxidation of the wafer and are correlated with the presence of a high density of shallow, flat-bottomed, saucer-shaped etch pits. The saucer pits are selectively annihilated in the diffused or im-planted regions during the fabrication of the Sb-doped buried collectors. For the ion-implanted process the annihi lation of saucer pits extends laterally from 50 to 100 ~m beyond the boundaries of the collectors. Following epi-taxial growth, epitaxial stacking faults, at a density of 104 cm-2, are only found in those nonburied layer regions which have a saucer pit density of 106-107 cm-2 before epitaxy. Therefore, epi stacking faults are not found in ion-implanted material with a separation between buried collectors of 100 gm or less. Most 3 in. diameter, and the central regions of 2 in. diamete