This paper investigates the ability of second harmonic generation (SHG) to probe the passivation quality of atomic layer deposited (ALD) 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 (µ-PCD) 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.

In this work, we investigate Second Harmonic Generation (SHG) as a nondestructive 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. 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.

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Here we present the characterization of dielectric-semiconductor interfaces using optical second harmonic generation (SHG). The technique is contactless, which makes it useful for non-destructive monitoring of ultra-thin dielectrics. The generated second harmonic is sensitive to material parameters and charges near interfaces. The signal exhibits time dependence due to charging of traps with carriers generated by the incident laser during the measurement. Quantitative models are applied to the time dependent SHG signals in the Al 2 O 3 stacks, which provide trapping kinetics information, and thus Al 2 O 3 film quality. Al 2 O 3 films are commonly used for passivating Si in photovoltaic stacks. To further demonstrate that time dependent behavior is due to changes in the electric field across the semiconductor/dielectric interface, additional systems are presented for comparison: SiN x on silicon, passivated and non-passivated silicon-on-insulator substrates. Results confirm the value of SHG as a quality control method for multiple thin film dielectrics.

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.