Hydrogen-implantation induced silicon surface layer exfoliation

The physical mechanisms of hydrogen-induced silicon surface cleavage were investigated using the combination of cross section transmission electron microscopy (XTEM) and Rutherford back-scattering spectrometry (RBS) channelling analysis. A [100]-oriented silicon wafer was implanted with 175 keV protons to a dose of 5 x 10(16) cm(-2). The implanted wafer was bonded to a SiO2-capped [100]-oriented silicon wafer and then heated to an elevated temperature of 600 degreesC to produce exfoliation. The damage region of the implanted silicon was examined by XTEM, which revealed the presence of hydrogen-filled platelets. The depth distribution of the implantation damage was also monitored by RES in the channelling condition in the as-implanted state as well as after the cleavage of the silicon wafer. A comparison of the RES and XTEM indicates that the nucleation of hydrogen-filled microcavities and the cleavage of the silicon wafer take place above the hydrogen concentration peak near the implantation damage peak, revealing the crucial role of the implantation damage in the crystal in terms of hydrogen-induced silicon surface layer exfoliation.