Characterization of thin doped silicon single crystals by x-ray diffraction

A free standing extremely thin silicon membrane, prepared by chemical vapor deposition of an epitaxial layer and subsequent anisotropic, selective etching has been studied. The epitaxial layerconsisted of a sandwich structure of undoped and highly boron/germainium doped films serving as an etch stop. The results of double- and triple crystal x-ray diffractometry in the Bragg and Laue case i.e. in reflection and transmission respectively are reported using a radiation between 5.05 (Cu K sub 1) and 17.5 keV Mo K sub 2).photon energy. The thickness of the crystal was determined to z sub o=30+1 My and its curvature to smaller than 7 10 high minus 4 m high minus 1. The inflluence of the doped etch stop layer on the x-ray reflectivity is discussed in detail.