Dynamical X-ray rocking curve simulations of 1.3micron light emitting diode wafers.

A catalog of theoretical double crystal rocking curves is presented for a range of layer thicknesses and mismatches encompassing ODL-200 specifications. Fits to rocking curve data for a 2 inch diameter wafer grown by hydride-VPE are also presented, and we conclude from the quality of the fit that this hydride- VPE grown LED base structure closely approached the hypothetical ideal assumed in the simulations. Since mismatch grading did not need to be included to produce good fits, the compositional uniformity was excellent. Furthermore, since there was no noticeable mosaic broadening, the LED structure was highly single crystalline. All the results are for a wavelength dispersion free double crystal arrangement using (400) reflections for both the sample and a (100) InP first crystal.