Layer structure analysis of Er delta-doped InP by x-ray crystal truncation rod scattering

The layer structure and crystal structure of an Er delta-doped layer in InP are analyzed in a one monolayer (NIL) level by an x-ray crystal truncation rod (CTR) scattering measurement using synchrotron radiation. The Er delta-doped InP sample is prepared by organometallic vapor phase epitaxy using trimethylindium, tertiarybutylphosphine, and tris(methyl-cyclopentadienyl)erbium as source materials. The analysis is made by comparing the measured CTR spectra and theoretically generated ones assuming four possible crystal structures for the Er delta-doped layers. We reveal that the Er atoms in InP form the rocksalt structure ErP. In the analysis of the crystal structure the x-ray interference plays a vital role. Er distribution in the delta-doped layer is clearly resolved in 1 ML level. It is shown that the Er atoms are well confined in 5 ML(15 Angstrom) thickness. The total amount of Er atoms is 0.171 ML, which is quite close to 0.2 ML obtained by Rutherford backscattering measurement on the same sample. (C) 1997 American Institute of Physics.