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Publication Citation: Grazing Incidence X-Ray Photoemission Spectroscopy and the Accuracy of Thickness Measurements of CMOS Gate Dielectrics

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Author(s): Terrence J. Jach; E Landree;
Title: Grazing Incidence X-Ray Photoemission Spectroscopy and the Accuracy of Thickness Measurements of CMOS Gate Dielectrics
Published: August 01, 2001
Abstract: Grazing incidence x-ray photoelectron spectroscopy (GIXPS) is a method that offers promise as a non-destructive technique to measure the thickness and chemical state of ultrathin gate dielectric films. This method utilizes the non-linear dependence of the photoelectron yield on the radiation incidence angle to characterize a given layer structure. The accuracy of the results also depends on the input parameters, such as photoemission cross-sections, indices of refraction and electron attenuation lengths within the incident x-ray energy range of application (1-2 keV). Uncertainties in these parameters have consequences not only for GIXPS but also for other techniques that rely on them for materials analysis. We present a study of the impact of uncertainty in the photoionization cross-sections and atomic scattering factors on the GIXPS measurement of film thickness and density. A test of the accuracy of the index of refraction is demonstrated by measurements of a native oxide layer on Si at incident energies below and above the Si K edge. We also discuss the effects of surface and interface roughness.
Citation: Surface and Interface Analysis
Volume: 31
Issue: No. 8
Keywords: GIXPS;grazing incidence;photoemission spectroscopy;TRXPS;x-ray;XPS
Research Areas: Spectroscopy