Strained-layer analysis with high-energy ion channeling

Abstract

Channeling with high-energy He or H ions offers enhanced angular resolution since the characteristic angle for channeling decreases with increasing energy. In this study channeling experiments with high-energy He ions (4–15 MeV) have been performed with the Eindhoven AVF cyclotron, carefully controlling important parameters such as beam divergence and target alignment. We applied high-energy ion channeling using a three-axis goniometer with high angular accuracy for strain analysis in Si/Si 1 − x Ge x /Si single-layer heterostructures with x = 0.175 and 0.05. The strain is derived from axial angular scans through the 〈110〉 and 〈111〉 directions in the {100} and {110} planes, respectively. The obtained scans are interpreted using the ion-trajectory simulation program LAROSE [J.H. Barrett, Phys. Rev. B 3 (1971) 1527]. The perpendicular lattice constant of the deformed Si 1 − x Ge x layers was determined with an accuracy comparable to the accuracy reached with high resolution X-ray diffraction.