MEASUREMENT OF DEPTH-DEPENDENT ATOMIC CONCENTRATION PROFILES IN CDTE HG1-XCDXTE STRUCTURES/

A novel method to obtain diffusion-controlled atomic concentration pro files in II-VI semiconductor heterostructures has been developed using high-resolution x-ray diffraction. Measured diffraction spectra are c ompared with simulations based on direct summation of scattered waves across the heterostructure. In this approach, short-range variations o f structural parameters, including the concentrations of the component s, interface roughness, etc., can be easily introduced into the simula tion routine. The application of the fitting procedure to the experime ntal spectra taken from variously annealed CdTe/Hg1-xCdxTe heterostruc tures grown by metal organic chemical vapor deposition, allowed determ ination of the Hg (or Cd) concentration depth profile as a function of the annealing temperature. As a result, the activation energy and the pre-exponential coefficient for mercury diffusion was found. The diff usion profiles derived from x-ray diffraction spectra were compared wi th secondary-ions mass spectrometry results, and the advantages of the new method are discussed. (C) 1997 American Institute of Physics.