Extended X-ray absorption fine structure spectroscopy has been used to
investigate the microscopic structure of InGaAs pseudomorphically gro
wn on a [001]GaAs substrate. The measure is restricted to the quasi-su
rface region of the epitaxial growth by means of the glancing-angle te
chnique. The results show that the strain is accommodated by bond-stre
tching and bond-bending and that the lattice expands in the growth dir
ection within the limits previewed by the elastic theory.