Measurement of the miscut angle of crystal surfaces vicinal to major crystal planes by X-ray diffraction at glancing incidence.

The width of an x-ray diffraction peak is a sensitive function of the angle of incidence when the angle of incidence is less than one degree. Measurements of x-ray diffraction peak widths taken at a glancing angle of incidence can be interpreted to yield information on miscut angles of crystal surfaces relative to major crystal planes. Miscut angles of a few arc minutes can be measured. A high-resolution multiple crystal x-ray diffractometer is necessary to achieve the accuracy of peak width measurement required. The technique is applicable to any crystal. As an example, we discuss the case of a (100) InP surface measured using the highly asymmetric (311) diffraction.