(12) , D Morresi (12) , M Garbarino (12) , G Alberti (13) , F Valdevit (13) , E Tomelleri (14) , M Torresani (14) , G Tonon (14) , M Marchi (15) , P Corona (15) , M Marchetti (16) Forest damage inventory after the "Vaia" storm in Italy On October 29, 2018, the Vaia storm hits the NorthEastern regions of Italy by wind gusts exceeding 200 km h-1. The forests in these regions have been seriously damaged. This contribution illustrates the methodology adopted in the emergency phase to estimate forest damages caused by Vaia storm, both in terms of damaged forest areas and growing stock volume of fallen trees. 494 Municipalities registered forest damages caused by Vaia, destroyed or intensely damaged forest stands amounted to about 42

Oxygen transport in and reactions with thin hafnium oxide and hafnium silicate films have been investigated using medium energy ion scattering in combination with 18 O 2 isotopic tracing methods. Postgrowth oxidation of Hf-based films in an 18 O 2 atmosphere at 490-950°C results in O exchange in the film. The exchange rate is faster for pure hafnium oxides than for silicates. The amount of exchanged oxygen increases with temperature and is suppressed by the SiO 2 component. Films annealed prior to oxygen isotope exposure show complex incorporation behavior, which may be attributed to grain boundary defects, and SiO 2 phase segregation.

Medium energy ion scattering (MEIS) has been used in combination with 16 O and 18 O isotope tracing to determine elemental depth distributions and elucidate oxygen transport in 2-5 nm thick HfO 2 and HfSiO x films grown by atomic layer deposition on Si(001). Both the oxygen isotope exchange rate in the dielectric as well as the interfacial silicon oxide growth rates were examined as a function of time, temperature, film stoichiometry (HfO 2 , HfSiO x and HfSiO x N y ) and crystallinity. The amount of exchanged oxygen in the oxide was found to decrease with increasing SiO 2 content. When the SiO 2 to HfO 2 ratio reaches 1:1 in HfSiO x almost full suppression of oxygen exchange is observed. The activation barrier for the SiO 2 growth at the HfO 2 /Si and HfSiO x /Si interface was found to be much lower than that in the SiO 2 /Si and SiO x N y /Si cases, which is attributed to distinctly different oxygen incorporation mechanisms.Primary route for oxygen delivery to the interface responsible for the SiO 2 growth is via exchange, however direct oxidation by molecular oxygen cannot be discounted completely. In the presence of an interfacial nitride layer the 18 O-16 O exchange is replaced by the 18 O-N exchange, which slows diffusion and reduces the oxidation rate.2

The properties of high-metal oxide gate stacks are often determined in the final processing steps following dielectric deposition. We report here results from medium energy ion scattering and x-ray photoelectron spectroscopy studies of oxygen and silicon diffusion and interfacial layer reactions in multilayer gate stacks. Our results show that Ti metallization of HfO 2 / SiO 2 / Si stacks reduces the SiO 2 interlayer and ͑to a more limited extent͒ the HfO 2 layer. We find that Si atoms initially present in the interfacial SiO 2 layer incorporate into the bottom of the high-layer. Some evidence for Ti-Si interdiffusion through the high-film in the presence of a Ti gate in the crystalline HfO 2 films is also reported. This diffusion is likely to be related to defects in crystalline HfO 2 films, such as grain boundaries. High-resolution transmission electron microscopy and corresponding electron energy loss spectroscopy scans show aggressive Ti-Si intermixing and oxygen diffusion to the outermost Ti layer, given high enough annealing temperature. Thermodynamic calculations show that the driving forces exist for some of the observed diffusion processes.

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Electrical activation of arsenic implanted in silicon on insulator (SOI) was studied. Two SOI structures with different Si overlayers and buried oxide thicknesses were used in this work. The As+ implantations were performed with a single energy of 20 keV to doses of 5 × 1014 cm−2 or 2 × 1015 cm−2 in both substrates. A plateau-like profile was achieved in an additional set of SOI samples by triple energy implantation. Rapid thermal and conventional furnace annealing were applied for dopant activation. Rutherford backscattering and Hall effect electrical measurements were done as well. The results are discussed, concerning electrical activation of As, considering the amorphization depth reached by dopant implantation and the crystal recovery process via thermal treatment. The completely amorphized samples presented higher values of sheet resistance and lower electrical activation percentage compared with the samples that did not have the complete top Si film amorphized. These results clearly show the need for avoiding total amorphization of the Si film during ion implantation in SOI, so that it is possible to achieve good crystal and electrical characteristics after thermal processing.

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We have studied arsenic (As) diffusion and its electrical activation in two different types of silicon substrates: bulk Si and separation by implanted oxygen (SIMOX) wafers. Both substrates were implanted with a dose of 5 ϫ 10 14 cm −2 As + at 20 keV. The samples were annealed and physical characterization was performed with secondary ion mass spectrometry (SIMS), Rutherford backscattering spectrometry, and medium energy ion scattering. The electrical properties of the film were extracted by Hall measurements. The SIMS results showed a lower dopant outdiffusion loss to the atmosphere during annealing in the SIMOX samples. The electrical results for the SIMOX samples were also superior to those of bulk Si due to the higher dopant retention, likely the result of a higher concentration of vacancies, which in turn increases the relative fraction of As which is activated (in substitutional sites). The net effect was a higher sheet carrier concentration and lower sheet resistance in the SIMOX samples. The implantation damage removal was superior in SIMOX samples compared to bulk Si ones.