Grazing-Incidence Diffraction Strain Analysis of a Laterally patterned Si wafer treated by Focused Ge and Au Ion Beam Implantation

Strain analysis of a laterally patterned Si-wafer was carried out utilizing X-ray grazing-incidence diffraction performed at the ID10B at the ESRF. The lateral patterning was done by focused ion beam implantation using a AuGeSi alloy liquid metal ion source. Samples were prepared by either a 35 keV Au+ ion beam (dose: 0.3, 2 ·10E14cm−2) or by a 70 keV Ge++ ion beam (dose: 8 · 10E14cm−2). It was shown that a periodical defect structure consisting of both implanted and not implanted stripes is created due to ion beam implantation. The induced strain distribution induced, however, shows no periodicity. This can be only explained by an overlap of the strain fields created in each implanted stripe. We found a maximum strain for the Au implanted samples in a depth of about 20 nm (da/a = −1,−3 · 10E−4 for the Au samples); for the Ge sample in a depth of 100nm (da/a = −1.2 · 10E−4). At depths 500nm below the sample surface the strain of the Ge sample becomes smaller than the detection limit (da/a < 2 · 10E−5). Using this technique we were able to create a buried Ge layer with a thickness of about 200 nm and an averaged Ge content of about 1%.