United States Government Publishing Office publisher pbl distributor dst United States Commerce Department National Institute of Standards and Technology (NIST) author aut Government Organization Sanford, Norman A. author aut text government publication eng GOVPUB Executive Agency Publications executive 2023-10-27 Commerce Department 2022-04-29 monographic deposited born digital 51 digital object pages C 13. https://www.govinfo.gov/app/details/GOVPUB-C13-93523dfbfecb66e718c4cdad91082c9d P0b002ee1c1bb3f5f on1389890383 (OCoLC)1389890383 DGPO 2023-10-27 2026-06-27 GOVPUB-C13-93523dfbfecb66e718c4cdad91082c9d machine generated eng fdlp C13 GOVPUB-C13-93523dfbfecb66e718c4cdad91082c9d 93523dfbfecb66e718c4cdad91082c9d GOVPUB NIST Technical Notes NOTE: THE “DATE ISSUED” ABOVE MAY DEFAULT TO JANUARY 1ST OF A GIVEN YEAR. TO THE VIEW THE MOST ACCURATE DATE OF ISSUE, REVIEW THE TITLE PAGE OF THE PUBLICATION. Studies or reports which are complete in themselves but restrictive in their treatment of a subject. Analogous to monographs but not so comprehensive in scope or definitive in treatment of the subject area. Often serve as a vehicle for final reports of work performed at NIST under the sponsorship of other government agencies. National Institute of Standards and Technology Commerce Department. National Institute of Standards and Technology. 2022 2022-04-29 https://www.govinfo.gov/app/details/GOVPUB-C13-93523dfbfecb66e718c4cdad91082c9d https://www.govinfo.gov/content/pkg/GOVPUB-C13-93523dfbfecb66e718c4cdad91082c9d/pdf/GOVPUB-C13-93523dfbfecb66e718c4cdad91082c9d.pdf Atom probe tomography Charge state ratio Field evaporation Gallium nitride III-nitride compound semiconductors Iridium Semiconductors Sanford, Norman A. creator Sanford, Norman A. Blanchard, Paul T. Brubaker, Matthew D. Rishinaramangalam, Ashwin K. Zhang, Qihua. Roshko, Alexana. Feezell, Daniel F. Klein, Benjamin D. B. Davydov, Albert V. National Institute of Standards and Technology (U.S.) Physical Measurement Laboratory mdu U.S. Dept. of Commerce, National Institute of Standards and Technology 2022-04-29. monographic 1 online resource (51 pages) : illustrations (color) text technical report eng Laser-assisted atom probe tomography (L-APT) was used to measure the indium mole fraction x of c-plane, MOCVD-grown, GaN/InxGa1-xN/GaN test structures and the results were compared with Rutherford backscattering analysis (RBS). Four separate sample types were examined with x = 0.030, 0.034, 0.056, and 0.11 as determined by RBS. The respective InxGa1-xN layer thicknesses were 330 nm, 327 nm, 360 nm, and 55 nm. L-APT data were collected under (fixed) laser pulse energy (PE)conditions in the range of (2 1000) fJ. Sample temperatures were generally 54 K. The data were analyzed using different region-of-interest (ROI) volumes to establish criteria for both data collection and compositional analysis that would return L-APT results that fell within the estimated 0.5 at. % uncertainty of RBS. Using cylindrical ROIs placed coaxially within the reconstructed InxGa1-xN regions, and with ROI depths of (55 180) nm, PE values in the range of(2 100) fJ yielded indium concentrations that conformed to RBS. L-APT results were comparatively insensitive to ROI diameter such that 20-nm-diameter coaxial ROIs yielded indium concentrations nearly equal to ROIs that encompassed the full InxGa1-xN regions. By contrast, for the GaN portions of the samples, L-APT would only yield near-stochiometric composition for PE in the range of (5 20) fJ with the analysis restricted to coaxial ROIs of diameters ?20 nm. m-plane oriented L-APT specimens were derived from core-shell GaN/InxGa1-xN multi-quantum-well structures. Analysis within ROIs placed along [0001] of these m-plane samples revealed a spatial asymmetry in charge-state ratios that is consistent with an electrostatic effect arising from spontaneous polarization. Both c-plane and m-plane sample types showed depth-dependent variations in absolute ion counts that depended upon ROI placement. Norman A. Sanford; Paul T. Blanchard; Matthew D. Brubaker; Ashwin K. Rishinaramangalam; Qihua Zhang; Alexana Roshko; Daniel F. Feezell; Benjamin D. B. Klein; Albert V. Davydov. April 2022. Title from PDF title page (viewed January 4, 2023). Includes bibliographical references. Approved by the NIST Editorial Review Board on 2018-02-25 Mode of access: World Wide Web. Systems requirements: Adobe Acrobat PDF reader. Iridium Gallium nitride Semiconductors Atom probe tomography Charge state ratio Field evaporation III-nitride compound semiconductors https://doi.org/10.6028/NIST.TN.2201