Study of Cu gettering to cavities in separation by implantation of oxygen substrates

Abstract

Gettering of Cu impurities to cavities induced in separation by implantation of oxygen (SIMOX) substrates has been investigated. The cavities were introduced beneath the buried oxide layer (BOX) of SIMOX by H+ implantation and subsequently annealing. 5×1013/cm2 or 5×1015/cm2 of Cu impurities were implanted in the top Si layer. The results indicate that the BOX layer does not appear to prevent the movement of Cu at temperatures higher than 700 °C. Profiles of Cu indicate that 92% of the initial 5×1013/cm2 Cu has diffused through the buried oxide layer and been captured by the cavities, with 1% of Cu left in the top Si layer after a 1000 °C annealing, and 73.6% of the 5×1015/cm2 Cu is gettered to the cavities with 13% of Cu in the top Si layer. The gettering effect of cavities is stronger than the damage around the BOX. H+ implantation-induced cavities have been demonstrated to be an effective method to getter Cu impurities away from the top Si layer in SIMOX substrates.