Relative lattice parameter measurement of sub-micron quaternary (InGaAsP) device structures grown on InP substrates.

Using X-ray diffraction techniques, one is able to routinely measure lattice parameters to several parts in 10(4) for microscopic specimens. However, measurements of lattice parameter changes for quaternary (InGaAsP) device structures several microns in width are not usually feasible with X-ray diffraction techniques. Convergent Beam Electron Diffraction (CBED), which is one of the techniques available on a modern transmission electron microscope (TEM), may be sensitive to these small, localized lattice parameter changes. Unfortunately, dynamical diffraction effects prevent direct extraction of changes in the lattice parameter from CBED patterns which are obtained from high atomic number materials. For this reason, we have chosen to calibrate the position of CBED features with X-ray lattice parameter measurements which were obtained from planar quaternary layers grown on InP substrates.