Improvements in investigation methods by X-ray topography. Applications to studies of semiconductor technology problems

The electrical performances of semiconductor electronic devices are liable to depend on the structural faults which exist in the starting material, or which are introduced into it by electronic devices fabrication technology. The present work shows some applications of X-ray topography to elucidate these structural defects in silicon. The examination method by X-ray topography is briefly discussed and the experimental set-up described. Results are presented in an analysis of the different types of faults created in silicon during integrated circuits fabrication steps: faults due to material growth, faults due to diffusions and thermal treatments. It will be shown that X-ray topography alone often is not sufficient to give a clear picture of formation and development of several types of faults, but must be assisted by other methods of characterization (chemical revelation, electron transmission microscopy). Finally the advantages of a double crystal diffraction method will be discussed. An apparatus using this method is presently being set up in the laboratory to complete classical X-ray topography. (author)