Synthesis of buried silicon oxide layers by water plasma immersion implantation

Buried silicon oxide layers were produced by water plasma immersion oxygen ion implantation and investigated by transmission electron microscopy, opti cal emission spectrometry, elastic recoil-detection analysis and Rutherford backscattering. Especially H2O+-ions, but also HO+-, O-2(+)- and Of-ions, were implanted into silicon by pulse biasing the silicon wafer to a voltage between -40 and -50 kV. The pulse duration was 15 mu s, the repetition rat e was 200 Hz and the pulse number was varied between 0.92 x 10(5) and 29.5 x 10(5) pulses. The temperature during implantation was between 420 degrees C and 800 degrees C. The subsequent annealing process at 1250 degrees C fo r 5 h leads to buried silicon oxide layers with smooth interfaces. The shap e of the oxygen concentration profiles is caused by superposition of the lo w-energy O+-ion and the high-energy H2O+- and HO+-ion profiles. The thickne ss of the damaged regions and the hydrogen contents decrease with increasin g temperature. The application of water plasma has the advantage that the i on range is about twice the given ion energy because ionized oxygen atoms a re implanted. (C) 1999 Elsevier Science B.V. All rights reserved.