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edfas.org ELECTRONIC DEVICE FAILURE ANALYSIS | VOLUME 19 NO. 4 18 the difference inmeasureddoping concentration, because SIMSmeasures the implanted doping density, and sMIM-C measures the activated doping concentration, as well as possible systematic variation during the measurements that could account for the discrepancy. It is expected for GaN that the activated doping concentration would be lower than the implanted density. The application of sMIM to a cleaved cross-sectional GaN device sample demonstrates the robustness of the method and the flexibility tomeasure doping levels on an unknown device sample using a known staircase for cali- brationof III-Vmaterials. Further refinements are ongoing. SUMMARY Scanningmicrowave impedancemicroscopy as a new mode for electrical measurements integrated to an AFM can address the needs of the semiconductor and failure analysis communities by providing increased sensitivity to investigate semiconductor devices for current andnext- generation technologies. Adoption of sMIM will enhance the available toolkit, especially in addressing quantifica- tion of doped semiconductors and dielectric materials. This article presents examples of some of the benefits of the sMIM technology: linear correlation to the log of dielectric coefficient; linear response to the log of doping concentration; visualization of metal, doped materials, and dielectrics in the same image; nanoscale C-V curves; and quantification of doping concentration on different classes of semiconductor materials. The AFM probes present specific challenges during measurements. This article shows results validating the authors’ models with comparison of the classic one- dimensional MOS model with a three-dimensional finite- element analysis cone-shaped model, confirming that using an AFM probe as an electrode for nanoscale C-V curves is different from those acquiredwith parallel-plate geometry but has similar potential for yielding quantita- tive characterizations. This article also shows that C-V curves can bemeasured fromdoped semiconductors and that they are consistent with what is predicted by theory for this type of three-dimensional geometry. The article also shows that single-bias images and single-point C-V measurements on an IMEC n - and p -type doped staircase sample are consistent and therefore can be used together to give an enhanced, quantitative view of a sample’s doping state. In addition, it has been shown that sMIM measurements on III-V semiconductor materials and silicon behave very similarly, so methods developed for the latter can be applied to the former; namely, a calibration from a known staircase sample can be applied to the sMIM image of an “unknown” device sample to estimate doping concentrations. REFERENCES 1. Y. Yang, E.Y. Ma, Y.-T. Cui, A. Haemmerli, K. Lai, W. Kundhikanjana, N. Harjee, B.L. Pruitt, M. Kelly, and Z.-X. Shen: “Shielded Piezoresistive Cantilever Probes for Nanoscale Topography andElectrical Imaging,” J. Micromech. Microeng., 2014. 2. N. Duhayon, T. Clarysse, P. Eyben, W. Vandervorst, and L. Hellemans: “Detailed Study of Scanning Capacitance Microscopy on Cross-Sectional and Beveled Junctions,” J. Vac. Sci. Technol. B: Microelectron. Nanometer Struct., 2002, 20 (2). 3. N. Duhayon, P. Eyben, M. Fouchier, T. Clarysse, W. Vandervorst, D. Álvarez, S. 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