Microstrain Analysis in Bent Single Crystal Silicon by Double Crystal X-Ray Topography Technique

摘要

In many important materials engineering applications such as integrated circuit devices, thin film amorphous solar cells, magnetic thin films and corrosion protection, it is important to obtain the maximum mechanical integrity of film-substrate interfaces in order to maintain uniformity of desired properties. Since the various deposition methods for fabricating film-substrate combinations produce internal strains in the material, it is convenient to devise a suitable method for monitoring these strains. Though limited in ultimate geometrical resolution, x-ray methods have the advantages of extremely high strain sensitivity and the ability to vary penetrating depth through the control of wavelength; they are nondestructive, and with modern computer control assistance, analysis can be made rapidly, accurately and safely. No commercial camera is currently available to fully exploit this new technology. The work reported within concerns the design and application of an automated Double Crystal X-ray Diffraction Topography camera capable of measuring radii of curvature over a range of 0.2 to 1000 meters for crystals bent due to internal stress. The corresponding strain sensitivity is of the order of 10 exp -7 . Calibration experiments showed that these determinations could be made with an accuracy of +- 10%. Observations using this technique are reported for several types of thin films on silicon substrates. (ERA citation 10:007296)