ABSOLUTE LATTICE-PARAMETER MEASUREMENT

The absolute lattice parameters of single- and polycrystalline materials have been measured to within a few parts per million with a high-resolution diffractometer. The problems associated with 'zero errors' and sample centring on the goniometer are eliminated and high precision is achieved by virtue of the exceedingly high angular resolution of the instrument. The high-resolution multiple-crystal multiple-reflection diffractometer is used to determine the lattice parameter with a single quick measurement on a range of 'perfect' semiconductor-substrate materials, layer structures and inhomogeneous samples. The various corrections and alignment procedures associated with this method are discussed.