Principles and Performance of a PC-Based Program for Simulation of Double-Axis X-Ray Rocking Curves of Thin Epitaxial Films

Abstract

ABSTRACTPC-based software for the rapid simulation of double-axis X-ray rocking curves from epitaxial thin films by solution of the Takagi-Taupin equations is described. The principles of the mathematical model are discussed. Graded layers and interface roughness are treated by piece-wise approximation to linear or quadratic functions and fractional relaxation of each epilayer may be included. The reliability of the data-bases incororated are examined and the requirement for internal consistency demonstrated. Bench-mark tests are reported for various PC-compatible microcomputers. The shift in epilayer peak position, which occurs experimentally on reducing layer thickness at constant composition, is predicted in the simulations and compared with other simulated data in the literature. Detailed studies of generated data have been undertaken and compared with independent simulations and experimental data. Agreement is excellent.