Verification of the Hypothesis on the Thermoelastic Nature of Deformation of a (0001)GaN Layer Grown on the Sapphire a-Cut

Semiconductors - The deformation of a (0001)GaN epitaxial layer on the (11 $$\bar {2}$$ 0) sapphire a-cut is studied by X-ray diffractometry. Anisotropic-layer deformation is calculated by...     

Analysis of the composition of (Al,Ga)As alloys by secondary ion mass spectroscopy and X-ray diffractometry

Calibration lines for the layer-by-layer analysis of the concentration of matrix elements in Al _x Ga_{1 ? x} As layers are obtained using a TOF.SIMS-5 secondary-ion mass spectrometer. The alloy concentration for the set of test samples was independently measured by high-resolution X-ray diffractometry allowing for deviation of the lattice constants and elastic moduli from Vegard??s law. It is shown that when using Cs⁺ sputtering ions and a Bi⁺ beam in secondary-ion mass spectrometry, the dependence of the intensity ratio Y(CsAl⁺)/Y(CsAs⁺) on x(AlAs) is close to linear for positive ions; and when detecting negative ions, the dependence Y(Al₂As^?)/Y(As^?) on x is close to linear. These data allow us to normalize the profiles of layer-by-layer analysis in the Al _x Ga_{1 ? x} As/GaAs system. In addition, a simple variant for the introduction of corrections to the deviation from Vegard??s law in the X-ray data is suggested.