Investigation for the Crystal Defects by X-ray Topography

Abstract

X-ray topography is a unique technique to visualize crystal defects, e.g., dislocations and stacking faults, for the whole wafer. It has more than 60 years history and still used for investigating quality of the crystals. For example, dislocation free Si single crystal wafer can be easily accessed at the present time. However, it could be often damaged and made defects at the device manufacturing process. Other newly developed single crystal materials, such as SiC and GaN are still having a lot of dislocations. The principle and instruments of the X-ray topography is briefly reviewed and presented how the dislocations are visible. Advanced three-dimensional topography and examples of in-situ topography observations are also introduced.