SURFACE X-RAY-DIFFRACTION STUDY ON THE SI(001)2X1 STRUCTURE

The atomic structure of the Si(001)2 x 1 clean surface has been invest igated by surface X-ray diffraction technique. Its sensitivity to both in-plane and out-of-plane directions has allowed three-dimensional an alysis of the atomic arrangement. The least squares fitting has given the asymmetric dimers whose bond length is 2.37 +/- 0.06 Angstrom and buckling angle is 20 +/- 3 degrees with the strain of the substrate ov er six layers. The resultant structure is similar to that of the Ge(00 1)2 x 1 surface.