The investigations of the structure parameters of Au-TiB2/GaAs and TiB2/GaAs device structures and their transformations at short-term thermal annealing were carried out. The metal films were magnetron sputtered on Czochralski-grown (001) GaAs in an argon atmosphere. The growth rate was similar to 5 nm/s and the film thickness ranged from 10 to 50 nm. The samples were annealed for 1 min at 400 degrees C, 600 degrees C and 800 degrees C. Using X-ray diffraction, scanning electron microscope (SEM) and scanning probe microscope (SPM) methods, it was shown that sputtering titanium diboride films causes the titanium and boron solid solutions to form as well as the appearance of some other phases in the interface region. Short-term annealing at above temperatures leads to elastic strain relaxation, changes of film morphology, decay of solid solutions and generation of dislocations. The relaxation processes differ for various types of structures.