Narrow fluence window and giant isotope effect in low-energy hydrogen ion blistering of silicon

We have found that blisters due to low-keV H-ion implantation and annealing of Si appear at low fluence (e.g., 2×1016 H cm−2) but disappear at slightly higher fluence (3.5×1016 H cm−2); this fluence “window” widens at higher ion energy. For D-ion blistering the window is shifted upwards by a surprising factor of 2–3. Thermal desorption spectrometry suggests that D is somehow more stable than H in Si. Hypotheses to explain blistering disappearance and the giant isotope effect are discussed. This phenomenon has an impact for the ion-cut process at the sub 100 nm scale.