Oxide interface studies using second harmonic generation

We report experiments using a non-invasive second harmonic generation (SHG) technique to characterize buried Si/SiO2 interfaces and also SIMOX thin film silicon-on-insulator (SOI) wafers. The measurements demonstrate that the SHG response can provide an indication of the quality of the buried oxide interfaces, by providing information on surface roughness, strain, defects, and metallic contamination. The potential application of SHG for comprehensive buried interface characterization and as a non-contact metrology tool for process control is described.