Defect and Diffusion Forum Vol. 265

Abstract: A trench is used as a storage capacitor in dynamic memory (DRAM) technologies (deep storage trenches), or as an isolation structure in CMOS, bipolar and BiCMOS technologies. But a shallow trench structure has also been shown to be a major factor in substrate defect generation during processing. Such defect generation is directly related to mechanical stresses existing around the trench. This stress can be monitored, using Raman spectroscopy, to a stress resolution of 10MPa and a spatial resolution of 0.2μm. In this paper, a trench structure is designed and fabricated, and the test results for local stresses within the trench are shown to be in good correspondence with theory.

Abstract: PLT and the Doppler broadening S-parameter were used to characterize the Al-Mg alloys, AA5005, AA5051, AA5052 and AA5083. The trapping efficiencies of these alloys were estimated to be 2.42 x 109, 2.29 x 109, 2.24 x 109 and 2.27 x 109 s-1 cm3, respectively, and the corresponding trapping cross-sections were estimated to be 2.66 x 10-16, 2.14 x 10-16, 2.10 x 10-16 and 3.51 x 10-16 cm2. It was found to be very clear that the mean lifetime and S-parameter exhibited the same behaviour as a function of the degree of deformation, and that they saturated at the same degree of thickness reduction.

Abstract: Positron annihilation has been performed in order to study the isochronal annealing of wrought (2024, 7075) and cast (AlSi11.35Mg0.23, AlSi10.9Mg0.17Sr0.06) aluminum alloys, at temperatures ranging from RT to 773K, after having been deformed at RT to 25% deformation. Two annealing stages of the microstructures were distinguished, which were attributed to recovery in (2024, AlSi11.35Mg0.23, AlSi10.9Mg0.17Sr0.06) due to point defects and dislocations, respectively, and only one (due to dislocations) in (7075). Also, natural aging for up to more than 650 days was studied as a function of mean lifetime.

Abstract: The method of Ionization Spectroscopy is used to study the thermo-induced kinetics of surface segregation of the Pt80Co20(111) alloy components. The temperature dependence of the Co diffusion coefficient in this alloy is determined. It is found that the value of the activation energy for the segregation of Co atoms in the near-surface region is close to the heat of sublimation of pure Co.