Second Harmonic Generation Characterization of SOI Wafers: Impact of Layer Thickness and Interface Electric Field

This paper presents Second Harmonic Generation (SHG) as a non-destructive characterization method for Silicon-On-Insulator (SOI) materials. For thick SOI stacks, the SHG signal is related to the thickness variations of the different layers. However in thin SOI films, the comparison between measurements and optical modeling suggests a supplementary SHG contribution attributed to the electric fields at the SiO2/Si interfaces. As a result of this behavior the SHG technique can be used to evaluate interfacial electric fields and consequently interface charge density in SOI materials.