Lattice parameter measurement of sub-micron device structures in compound semiconductors via convergent beam electron diffraction.

Convergent-beam electron diffraction (CBED), which is one of the techniques available on a modern transmission electron microscope (TEM), is sensitive to small localized lattice parameter changes and its application is therefore important in the characterization of sub-micron device structures. Unfortunately, dynamical diffraction effects prevent direct extraction of changes in the lattice parameter from CBED patterns which are obtained from high atomic number materials such as compound semiconductors. Therefore, in order to measure the relative lattice mismatch of a quaternary (InGaAsP) device structure grown on InP, we have opted to calibrate the relative position of CBED features with X-ray lattice parameter measurements which were obtained from planar quaternary layers grown on InP substrates.