The Si Nanocrystal Trap Center Studied by Deep Level Transient Spectroscopy (DLTS)

Abstract

Si nanocrystal (NC) embedded into the SiO2matrix was made by SiO/SiO2superlattice method. Here we investigate the storage phenomena of MOS structure having Si NC inside the dielectric layer by high frequencyC-Vmethod and DLTS. DLTS treated the individual Si NC as a single point deep level defect in the oxide and revealed essences of Si NC storage, such as a large capture cross section at about 1–7 × 10−13 cm2and potential barrier at about 1.6 eV. These two properties we observed are consistent with Si NC dimensions of 5–7 nm in the planar TEM image, and previousI-Vcharacterization in the MOS-like structure. These results are helpful to understand the principle of charge storage of this structure and optimize the performance of real Si NC device. The trapping mechanism in MOS systems containing Si NCs is related to the quantum levels of the Si NC band structure at around 300 K.