The influence of hydrogen dose and boron doping on the ion-cutting of Si

Ion beam techniques were used to study silicon‐on‐insulator (SOI) structures manufactured by the ion cutting process. Silicon wafers and epitaxial Si layers with various doping levels were implanted with H₂⁺ ions at 100 keV prior to wafer bonding. Some wafers were also implanted with B⁺ ions at 175 keV. The implantation doses varied from 2.5 × 10¹⁶ to 5.0 × 10¹⁶ cm⁻² for H₂⁺ and from 1 × 10¹³ to 3 × 10¹⁵ cm⁻² for B⁺. The thickness of an SOI layer was determined by conventional Rutherford backscattering spectrometry (RBS) and the crystal damage was examined by RBS in channelling mode (RBS/C). The disorder due to implanted hydrogen was found to decrease with increasing boron concentration. The measured thickness of the exfoliated Si layer was 455–460 nm for highly boron‐doped samples and 470–490 nm for the undoped samples. Exfoliation occurred inside the damage zone in all the samples, irrespective of hydrogen dose and boron doping. Our results suggest that the exfoliation depth in Si is associated with the lattice damage generated by the implantation.