Ion cutting and transfer of sub-100-nm silicon layers using low-keV H, D, and He ions

The authors have investigated the ion cutting and transfer of silicon layers thinner than 100nm using 5–8keV H, D, or He ions. The thickness and morphology of the transferred layers have been characterized as a function of ion fluence. Ion cutting of bonded layers occurs in a much wider fluence range than blistering of free surfaces. The optimal surface roughness (2nm) is obtained with rather high H or D doses of (7–8)×1016at.∕cm2, although the threshold dose is 1.5×1016H∕cm2 only. These results demonstrate the importance of the boundary conditions imposed on the splitting process by the bonded wafer.