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Optical second harmonic generation (SHG) can be employed to characterize the passivation quality of semiconducting material interfaces. The interface electric field (EDC) related to the existing charges at and near the interface, including the fixed oxide charges Qox, gives rise to the electric field induced second harmonic phenomenon. In this paper, we calibrate the SHG response for EDC measurement, using Al2O3/SiO2/Si(100) samples with different Qox. To perform this calibration, SHG and capacitance-voltage measurements (to access the electrical field of the samples) were made. The experimental results match well the simulated calibration curve, proving the potential of the SHG as stand-alone characterization technique for dielectric stacks on Si. [ABSTRACT FROM AUTHOR]

Second harmonic generation (SHG) is used to characterize the interfaces of centrosymmetric materials typically used in microelectronic/optoelectronic devices. For such applications, the materials are actually multi-layer stacks, and in this case, the SHG can be difficult to interpret and model. This paper presents the theory of the second harmonic light generated from multilayer structures. The focus is on describing the nonlinear boundary conditions at the interfaces between two different materials, taking into account the distinct contributions of bulk and interface regions. Using these conditions, it is possible to calculate the second harmonic signal from any stack of materials. In this paper, we address stacks containing silicon (100) because it is a material with numerous applications. The nonlinear polarization expressions of the surface and bulk of Si(100), according to Sipe et al. [Phys. Rev. B 35, 1129 (1987)], were integrated into nonlinear boundary conditions in order to determine transmitted and reflected second harmonic waves. An analytical validation was performed on the simple case of an air–silicon interface. For multilayered stacks, the model was compared with experimental results obtained on samples corresponding to pragmatic substrates widely used in microelectronic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

This paper investigates the ability of second harmonic generation (SHG) to probe the passivation quality of atomic layer deposited Al2O3 on Si by estimating the induced interface electric field due to fixed charges in the oxide. Samples with various oxide charges (Qox) and interface state densities (Dit) were fabricated, using different deposition parameters. The samples were characterized by capacitance-voltage (C-V) and microwave photoconductance decay measurements in order to evaluate Qox and Dit, as well as the effective minority carrier lifetime τeff. The SHG results were consistent with Qox, Dit, and τeff values, proving the ability of the technique to monitor the interfacial quality in a contactless and non-destructive way. Optical simulations which use the electric field values obtained from the C-V measurements could reproduce the measured SHG signal. This demonstrates that SHG coupled with optical simulation can give access to the electric field magnitude and thus characterize the electrical properties of oxide/Si interfaces. [ABSTRACT FROM AUTHOR]

In this work, we investigate 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 SiO 2 /Si interfaces. The impact of the electric field at each interface of the SOI on the SHG is assessed. The SHG technique can be used to evaluate interfacial electric fields and consequently interface charge density in SOI materials. [ABSTRACT FROM AUTHOR]

In this work we investigate a non-invasive, non-destructive characterization technique for monitoring the quality of film, oxide and interfaces in silicon-on-insulator (SOI) wafers. This technique is based on optical Second Harmonic Generation (SHG). The principles of SHG and the experimental setup will be thoroughly described. The experimental parameters best suited for testing SOI wafers with SHG are identified. SOI geometry, as well as the passivation of the top surface, both have an impact on the observed SHG signal. The back-gate bias applied on the substrate is shown to modulate the SHG signal. [ABSTRACT FROM AUTHOR]