CHARACTERIZATION OF TERNARY SUBSTRATE MATERIALS USING TRIPLE AXIS X-RAY-DIFFRACTION

We have developed triple axis X-ray diffraction to simultaneously dete rmine the lattice parameter and crystalline perfection of ternary Cd1- yZnyTe and Ga1-xInxAs boules. The lattice parameter is obtained with a n accuracy of better than a few parts per 10(5), and the alloy composi tion is determined (+/- 0.001 in mole fraction) through a combination of symmetric and asymmetric reflections and use of Vegard's law. Cryst alline perfection is assessed by the Cull width at half maximum values from triple axis rocking curve measurements. Maps of both composition and crystalline quality as a function of position were also generated to demonstrates alloy segregation and the relationship between crysta lline perfection and segregation. The usefulness of this nondestructiv e characterization technique is illustrated for the case of Cd1-yZnyTe radiation detectors where it is shown that the triple axis rocking cu rve full width at half maximum values correlate strongly with detector performance but there is little influence of variations in alloy comp osition on detector performance.