Person:
González Díaz, Germán

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First Name
Germán
Last Name
González Díaz
URI
https://hdl.handle.net/20.500.14352/75016
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Estructura de la Materia, Física Térmica y Electrónica
Area
Electrónica
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2002 - 20053
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Author: San Andrés Serrano, Enrique × Has files: false ×

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Now showing 1 - 3 of 3
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    Rapid thermal annealing effects on the electrical behavior of plasma oxidized silicon/silicon nitride stacks gate insulators
    (Journal of Vacuum Science & Technology B, 2003) Martil De La Plaza, Ignacio; González Díaz, Germán; Prado Millán, Álvaro Del; San Andrés Serrano, Enrique
    We present a comparative study of the electrical and structural characteristics of metal-insulator-semiconductor (MIS) devices using SiN1.55:H or SiN1.55:H/SiOx stacks as gate dielectrics, with the aim of improving the thermal stability of the SiN1.55:H/Si interface. The dielectrics were grown on Si by the electron cyclotron resonance plasma method. The stacks were produced by plasma oxidation of the Si surface, resulting in a thin layer of SiOx (PO-SiOx), followed by deposition of the SiN1.55:H layer. Afterwards, the samples were rapid thermally annealed (RTA) at temperatures ranging from 300 to 1000degreesC. Some representative samples were studied by Fourier transform infrared spectroscopy to characterize the bonding structure of the SiN1.55:H/PO-SiOx stack and its evolution with the annealing temperature. The results were in good agreement with the well known model for suboxide evolution with the temperature: the formation of highly defective nanocrystalline Si clusters inside a high quality SiO2 matrix. This process takes place for RTA temperatures higher than 700degreesC. This model also explains the results derived from C-V measurements, which show improvement of the PO-SiOx/Si interface as a result of the formation of the high quality SiO2 matrix. Additionally, the thermal stability improved with respect to the SiN1.55:H/Si interface, which suffers significant degradation when annealed above 600degreesC, while devices made with the stacks are able to hold annealing temperatures up to 900degreesC. On the other hand, the formation of nc-Si results in degradation of the reliability of the MIS devices.
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    Physical properties of high pressure reactively sputtered TiO2
    (Journal of Vaccum Scuebce & Technology A, 2005) Martil De La Plaza, Ignacio; González Díaz, Germán; Prado Millán, Álvaro Del; San Andrés Serrano, Enrique
    We present a study of the physical properties of TiO2 thin films deposited at 200 degrees C on Si by high pressure reactive sputtering, a nonconventional deposition method. Just after deposition, the TiO2 films were in situ annealed in the deposition chamber at temperatures between 600 and 900 degrees C in O-2 atmosphere. Morphological, compositional, structural and electrical characterization of the samples was performed by means of several techniques, including transmission electron microscopy, heavy-ion elastic recoil detection analysis, infrared spectroscopy, x-ray and electron diffraction and capacitance-voltage measurements. Microscopy images show that the TiO2 films are polycrystalline, and that a SiO2 film spontaneously grows at the TiO2/Si interface. The unannealed TiO2 films are oxygen rich, as shown by compositional measurements. By annealing this oxygen excess is released. For temperatures above 600 degrees C the TiO2 films are stoichiometric. Infrared spectroscopy and diffraction measurements show that as-deposited films are a mixture of anatase and rutile grains. During annealing there is a phase transformation, and at 900 degrees C the anatase phase disappears and only the rutile phase is found. The relative dielectric permittivity of the TiO2 film is calculated from capacitance-voltage measurements, and very high. values in the 88-102 range are obtained.
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    Compositional analysis of SiOxNy : H films by heavy-ion ERDA: the problem of radiation damage
    (Surface and interface analysis, 2002) Martil De La Plaza, Ignacio; González Díaz, Germán; Prado Millán, Álvaro Del; San Andrés Serrano, Enrique
    Films of SiOxNy:H were deposited at room temperature on Si substrates by the electron cyclotron resonance (ECR) plasma method. By varying the flow rates of the precursor gases SiH4, O-2. and N-2, the whole composition range between pure silicon oxide and nitride could be covered. Heavy-ion elastic recoil detection analysis (HI-ERDA) with a 150 MeV Kr-86 ion beam and time-of-flight (ToF) mass separation was applied to determine the absolute atomic concentrations of all film components, including hydrogen. Additionally, the bonding configuration of the films was studied by infrared (IR) spectroscopy. Extended ion beam exposure was found to decrease the intensity of the N-H phonon band as well as the nitrogen and hydrogen concentrations. By storing the ion scattering data event by event and by recalculating a zero-dose composition, this effect was taken into account. The corrected Hl-ERDA results revealed clear relations to the deposition parameters (e.g. the O-2/SiH4 flow ratio). The hydrogen incorporated in the films turned out to be bonded predominantly to nitrogen. The damage effects were strongest in the medium composition range. They were found to scale with the relative concentration of SiO2N2-type basic tetrahedrons, suggesting that this bonding configuration is most sensitive against irradiation during the HI-ERDA measurement. Copyright (C) 2002 John Wiley Sons, Ltd.