In-situ observation of surface blistering in silicon by deuterium and helium ion irradiation

Blistering processes on crystalline silicon surfaces were observed in situ by grazing incidence electron microscopy (GIEM) under deuterium (D+) and helium (He+) ion irradiation. In D+ irradiation, the size and density of the blisters were significantly reduced in the continuously electron-illuminated area. This is attributed to the incident high-energy electrons, which suppress the formation of deuterium terminated cracks by electronic excitation effect. It was also found that irradiation at a higher ion flux give rise to catastrophic flaking before well-separated blisters were formed. In addition, the present study strongly suggests that the crack formation and propagation under D-irradiation start preferentially around the most heavily damaged depth rather than the peak projected range of the implanted D atoms.