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Continuous miniaturization of integrated circuits requires narrower dopant profile depth in the Si channel and consequently the use of ultra-shallow implants in the manufacturing process. Secondary Ion Mass Spectroscopy (SIMS) is routinely used to measure the boron depth concentration profiles. However, due to the altered nature of the near-surface sputtering process inherent to SIMS, it underestimates the B implanted doses for implantation energies below 2 keV. Alternate ion beam methods for absolute dose measurements of ultra-shallow implanted As and B in Si are presented in this study. The dopant implant energies ranged from 250 eV, to 5 keV for boron and from 500 eV to 5 keV for arsenic. Implanted doses for both B and As varied from 2 × 1013 to 1 × 1015 atoms/cm2. The arsenic implants were studied with Rutherford Backscattering Spectrometry (RBS) using 2 MeV carbon ions. The absolute arsenic implanted doses were measured to an accuracy of better than 5%. The 1 keV arsenic implants were extensively studied for radiation damage with a 12C beam. No appreciable arsenic dose loss was observed during C irradiation for an integrated charge of ≤ 80 μC, which was the maximum used for these studies. For the B implants, Elastic Recoil Detection (ERD) was used with 14 MeV F4+ ions. A 9.4 μm Mylar foil was found to adequately stop the scattered 19F ions and give good energy separation for the 11B recoiled ions. The absolute dose measurements are ∼ 5% for the 5 keV 11B implants. Significant radiation damage was observed for the ultra shallow implants and the measured B dose has been obtained by extrapolation to the zero integrated charge of the beam. The absolute boron dose measurements of the ultra shallow (250 eV) implants were determined with an accuracy better than 10%. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

The knowledge of (diffusion, drift, and funneling assisted) charge collection within electronic devices is essential to design radiation hardened Integrated Circuits (ICs). In the present work, diffusion time resolved charge collection studies were performed on stripe-like junctions using 12 MeV carbon and 28 MeV silicon microbeams and MEDICI simulation calculations. The relative average arrival time of the diffused charge on the junctions was measured along with the amount of charge collection by the junctions. The average arrival time of the diffused charge is related to the first moment (or the average time) of the arrival carrier density on the junction. The experimental results and MEDICI (a 2D-device simulator) calculations support this interpretation. These results show the importance of the diffusive charge collection by junctions, which is especially significant in accounting for Single Event Upsets (SEUs) and Multiple Bit Upset (MBUs) in digital devices. [ABSTRACT FROM AUTHOR]

Traditionally, [sup 90]Y obtained from a [sup 90]Sr/[sup 90]Y generator contains a small concentration of [sup 90]Sr (range: 1μCi [sup 90]Sr/100mCi to 1 Ci [sup 90]Y) and due to the 28.78 y half-life of [sup 90]Sr, special waste handling and storage is required. In this study, the medical isotope [sup 90]Y has been produced by an alternate method using the [sup 90]Zr(n,p)[sup 90]Y reaction. Neutrons for the activation process were produced using [sup nat]Rh(p,xn) reaction with a 27 MeV proton beam from a cyclotron. Since [sup 90]Y is a pure beta emitter, the gamma rays from the [sup 90]Zr(n,2n)[sup 89]Zr reaction were used to quantify the incident neutron flux on the [sup 90]Zr sample. Experimental results of the neutron production and [sup 90]Y activity are presented. [ABSTRACT FROM AUTHOR]

The paper reports the recent progress of a high-energy, heavy ion nuclear microprobe facility established at the University of North Texas. The microprobe system is installed on a 3MV NEC 9SDH-2 Pelletron tandem accelerator. A high demagnification factor (∼60) has been achieved with the system, using a probe-forming lens system (from MARC, Melbourne, Australia) with the new Russian quadruplet configuration. The spatial resolution of 2-3 µm has been achieved for 4.0 MeV carbon ions or 9.0 MeV alpha particles with a beam current of ∼ 50-100 pA. Better spatial resolution (approaching one µm) is achievable when an extremely low beam current (100-2000 ions/sec) is used in the applications of IBICC and IBIL. Applications of the analytical techniques with the nuclear microprobe are outlined and discussed. [ABSTRACT FROM AUTHOR]

Ion Beam Induced Luminescence (IBIL) and Ion Beam Induced Charge Collection (IBICC) have been used to study the efficiency and the homogeneity of the luminescence emission in phosphors. The IBIL imaging was made by using sharply focused ion beams or broad/partially-focused ion beams. Samples were examined to reveal possible distributed crystal-defects that may lead to the inhomogeneity of the luminescence emission. The purpose of the study is to search for suitable thin films that have high homogeneity of luminescence emission and large IBIL efficiency under heavy ion excitation. These films may be placed as a thin layer on the top of microelectronic devices to be analyzed with Ion Photon Emission Microscopy (IPEM). The emission yields were found to be low for organic materials, due to saturation of the light output dependence on the energy deposition of heavy ions. The emission yield of a typical Bicron plastic scintillator is about 70 photons/ion/micron. Inorganic materials may have higher IBIL yields under high-energy and heavy-ion excitation, but the challenging problem is the inhomogeneity of the IBIL emissions. The IBIL image techniques are applied in the investigation of the homogeneity of a GaN epitaxial thin film, a zircon single crystal and a thin layer coated by Thiogallate (EuII) ceramic. [ABSTRACT FROM AUTHOR]