STUDY OF CU GETTERING TO CAVITIES IN SEPARATION BY IMPLANTATION OF OXYGEN SUBSTRATES

Gettering of Cu impurities to cavities induced in separation by implan tation of oxygen (SIMOX) substrates has been investigated. The cavitie s were introduced beneath the buried oxide layer (BOX) of SIMOX by Himplantation and subsequently annealing. 5 x 10(13)/cm(2) or 5 x 10(15 )/cm(2) of Cu impurities were implanted in the top Si layer. The resul ts indicate that the BOX layer does not appear to prevent the movement of Cu at temperatures higher than 700 degrees C. Profiles of Cu indic ate that 92% of the initial 5 x 10(13)/cm(2) Cu has diffused through t he buried oxide layer and been captured by the cavities, with 1% of Cu left in the top Si layer after a 1000 degrees C annealing, and 73.6% of the 5 x 10(15)/cm(2) 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 f rom the top Si layer in SIMOX substrates. (C) 1998 American Institute of Physics.