Ordering at Si(111)/a-Si and Si(111)/SiO(2) interfaces.

X-ray diffraction has been used to measure the intensity profile of the two dimensional rods of scattering from a single interface buried inside a bulk material. In both the Si(111)/a-Si and Si(111)/Si0(2) examples considered there are features in the perpendicular momentum transfer dependence which are not expected from an ideal sharp interface. Modeling the amorphous material with partial order into layers adjacent to the interface agrees with the diffraction profiles very well.