Investigation of surface blistering of hydrogen implanted crystals

The time required to observe the onset of blistering was measured for 100 keV H implanted Si, SiC, and Ge crystals as a function of dose and annealing temperature. The calculated blistering activation energy (EA) for Si was found to decrease rapidly with increasing H dose. In Ge, EA decreased only slightly, while EA did not vary with dose in SiC. Hydrogen profiling using the H1(N15,αγ)C12 technique was used to study the evolution of the H distribution in these crystals. It was observed that implanted H concentrates upon annealing in Si and SiC, but not in Ge. By measuring the H profiles on the surfaces of bonded and transfered Si layers it was concluded that fracture occurred at the H peak and 50% of the implanted H was liberated during fracture. Ion beam channeling using 2 MeV He4 was used to study the implant damage in these materials. The dechanneling levels in the channeling spectra were attributed to the presence of lattice distortions near the implant peak. It was determined that the extent of lattice distortion was greatest in Ge and least in SiC. An observed decrease in the dechanneling level in as-implanted Si above 9×1016 H/cm2 was attributed to strain relaxation during implantation. Amorphization in SiC dramatically decreased the growth rate of the microcracks, implying that amorphous materials may be difficult to use in conjunction with Smart-Cut™ technology.