Crystalline quality of bonded silicon-on-insulator characterized by spectroscopic ellipsometry and Raman spectroscopy

摘要

The crystalline quality of silicon-on-insulator fabricated by a wafer bonding technique was examined by spectroscopic ellipsometry and Raman spectroscopy. The detailed modeling of the experimental ellipsometric data yields information about structural defects in the silicon-on-insulator layer. The dielectric function of the silicon on insulator that best models the experimental ellipsometric data includes a physical mixture of crystalline silicon and about 4%-7% of amorphous silicon, suggesting a slight lack of long-range order of the silicon atoms in the silicon-on-insulator layer. The use of a dielectric function other than that of pure crystalline silicon is supported by Raman spectroscopic results that indicate the presence of structural defects in the silicon-on-insulator layer. These structural defects may be due to the effects of hydrogen implantation used in the fabrication process of silicon-on-insulator, and/or the strain imposed by the lattice mismatch between the buried layer and the silicon substrate, and subsequently relaxed under high-temperature annealing. (C) 2004 American Institute of Physics.