Comparison of Cu gettering to H+ and He+ implantation-induced cavities in separation-by-implantation-of-oxygen wafers

Well-defined bands of cavities have been formed beneath the buried oxide (B OX) layer of two sets of separation-by-implantation-of-oxygen (SIMOX) wafer s by H+ and He+ implantation. The gettering of Cu impurities, which were im planted into the top Si layer at different doses (5 X 10(13), 5 X 10(14), a nd 5 X 10(15)/cm(2)), to the cavities has been studied by secondary ion mas s spectroscopy and cross-sectional transmission electron microscopy. The re sults indicated that the cavities induced either by H+ or He+ implantation are effective gettering centers for Cu in SIMOX wafers, and up to 4 X 10(15 )/cm(2) Cu has diffused through the BOX layer and been captured by the cavi ties. The gettering efficiency of cavities increases with the decrease of C u implantation doses and the increase of annealing temperatures. He+ ion im plantation is found to be more suitable for cavity formation and impurity g ettering than H+ ion implantation. (C) 1999 American Institute of Physics. [S0021-8979(98)06524-4].