Measuring interface strains at the atomic resolution in depth using x-ray Bragg-surface diffraction

摘要

A generic x-ray diffraction method, using three-wave Bragg-surface diffraction, is developed to measure strains at the interface of molecular beam epitaxial Au/GaAs(001), where grazing-incidence diffraction cannot be applied due to the difference in refractive index between Au and GaAs. Changes in diffraction images of the surface reflection (1-13) of GaAs(006)/(1-13) three-wave Bragg-surface diffraction and the (-1 - 13) of GaAs(006)/(-1 -13) at different azimuth and Bragg angles give the depth penetration of 2 A resolution and variations of lattice constant, -49%, -27%, and 2%, along the surface normal [001] and in-plane directions [-1-10] and [1-10] within the depths of 18, 72, and 72 A, respectively.