(The) effects of the $Si/SiO_2$ interface structure on electrical and optical properties

Abstract

The $Si/SiO_2$ interface is a key issue in electronic and optoelectronic device. In elctronic device, the $SiO_2$ thin film on Si has been used as a gate dielctric which is the most thin layer in silicon-based metal oxide semiconductor field effect transistors(MOSFETs). While the thickness of gate oxide in 1 Gbit DRAM is about 5 nm, the thickness of the transition region at the $Si/SiO_2$ interface has been reported to vary from 0.5 to 3 nm. The interface region occupies a large portion of the gate oxide and therefore not negligible. Though it is now well established that ULSI reliability and electrical properties are strongly dependent on the quality of the silicon-gate oxide interface region, relatively little is known about the atosmic configuration of these defects, especially for ultrathin oxide film. The $Si/SiO_2$ interface is also important fact in optical applications. Si nanostructures, such as porous Si, quantum dots in $SiO_2$ matrix, and $Si/SiO_2$ superlattices, and Er-doped Si nanostructures have drawn a great attention as candidates for Si-based integrated optoelectronic device materials. Although it is argued that the $Si/SiO_2$ interface states play some roles in light emission, the details are still controversial. It is necessary to find out the atomic configuration of the interface like as the gate oxide for more understandings. In this study, we have constructed UHV - ion beam sputter deposition system for in-situ MEIS analysis. We can control the composition, the thickness, and the structure of the films down to sub-monolayer with this system. We could make the $Si/SiO_2$ superlattice which has high light emission efficiency though we could not obtain the $SiO_2$ films with high electric quality. So the sample for electrical measurements was made in samsung electronic cooperation. We have measured the composition and strain profile of the $Si/SiO_2$ interface with Medium Energy Ion Scattering Spectroscopy (MEIS) which has atomic scale dep...