Sensitivity of X-ray diffractometry for strain depth profiling in III–V heterostructures

The use of the fine structure of X-ray rocking curves for the characterization of the abruptness of heterointerfaces is presented for the particular example of Ga_1−xAl_xAs/GaAs heterojunctions. The sensitivity of the method is discussed in detail for the 400 reflection with two different wavelengths (1.2378 and 1.5410 Å). It is shown that the conclusions can be extended to other reflections and wavelengths provided that the ratio χ_hi/χ_hr depending on both the absorption and the strength of the reflection is kept below 10⁻¹.