PROXIMITY GETTERING OF COPPER IN SEPARATION-BY-IMPLANTED-OXYGEN STRUCTURES

Gettering of copper to carbon- or helium-implanted regions introduced at different depths in separation-by-implanted-oxygen (SIMOX) wafers i s studied by means of secondary ion mass spectroscopy (SIMS). The fina l Cu redistribution appears to be modified depending on the depth loca tion of the proximity gettering layers. It is shown that both C and He implants can provide efficient protection against Cu contamination, i f these are positioned at a sufficiently large depth beneath the burie d oxide. A proximity-gettering scheme using deep C implantation may be preferable as the C dose necessary to achieve one and the same extent of the gettering effect is much lower than the respective He dose.