Abstract
The blistering of Si wafers with (100), (110), and (111) orientations, induced by implantation of low energy (5–8 keV) H and/or He ions, was studied. Our earlier work had used either pure H implants at high dose (5×1016 cm−2) or low dose coimplantation (1×1016 H cm−2+1×1016 He cm−2). Here we study pure He implantation, and coimplantation with variable He/H dose ratio, in order to understand the roles of H and He, in the hope of improving the blistering efficiency (as used, e.g., in the Smart-cut® process). After room temperature implantation, the samples were vacuum annealed in three steps at 500, 550, and 600 °C. At each step, the development of blistering and exfoliation was quantified by scanning electron microscopy (“exfoliation” is here used to mean blister explosion). We found that the thermal budget required for blistering is higher than for comparable doses of high energy (>30 keV) ions. On the Si(110) surface, H blistering is very weak, He blistering is the strongest, but exfoliation absent. On Si(111), H blistering is the strongest, He the weakest, but exfoliation a maximum. Si(100) shows intermediate behavior. Weak H blistering correlates with premature H2 desorption. H+He coimplantation efficiently increases the degree of blistering and, to some extent, exfoliation.

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