AVS 45th International Symposium
    Surface Science Division Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM10
Surface Structural Study of Ultra-Thin Si (111) on SiO@sub 2@

Wednesday, November 4, 1998, 11:20 am, Room 308

Session: Physics of Semiconductors
Presenter: M. Noh, University of Tennessee and ORNL
Authors: M. Noh, University of Tennessee and ORNL
A.P. Baddorf, Oak Ridge National Laboratory
H.H. Weitering, University of Tennessee and ORNL
Correspondent: Click to Email
Si on insulator (SOI) material is important for extension of metal-oxide silicon (MOS) technology development in the next generation of microelectronics. Technological requirements have led to interest in very thin SOI layers. The surface structure of ultra-thin layers of (111) oriented SOI has been investigated for the first time, using low energy electron diffraction (LEED) and scanning tunneling microscopy (STM). SOI samples were prepared using the Separation by Implanted Oxygen (SIMOX) method, then characterized by Rutherford backscattering spectrometry (RBS) to determine the thickness and quality of the Si overlayer. LEED observations from a 2000 Å thick Si layer on 5000 Å SiO@sub 2@ reveal a sharp 7x7 diffraction pattern, well known for bulk Si (111) surfaces. STM images of the same surface show nearly defect free 7x7 surface reconstructions with terrace lengths exceeding 1000 Å. These observations reveal that the surface of a thin Si (111) film on SiO@sub 2@ can be fabricated with a comparable degree of structural perfection as the (111) surface of bulk Si. The quality of the (111) SOI surface was monitored as a function of Si top layer thickness after thinning by dry oxidation and stripping. Results are compared to previous images of (100) SOI surfaces.@footnote 1,2@ @FootnoteText@ @footnote 1@K.C. Lin, O.W. Holland, L.C. Feldman, and H.H Weitering, Appl. Phys. Lett. 72 (1998) 2313. @footnote 2@Oak Ridge National Laboratory (ORNL) is managed by Lockheed Martin Energy Research Corp. for the U. S. DOE under contract number DE-AC05-96OR22464.