8 results on '"Bender, Hugo"'
Search Results
2. Intragrain defects in polycrystalline silicon layers grown by aluminum-induced crystallization and epitaxy for thin-film solar cells.
- Author
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Van Gestel, Dries, Gordon, Ivan, Bender, Hugo, Saurel, Damien, Vanacken, Johan, Beaucarne, Guy, and Poortmans, Jef
- Subjects
POLYCRYSTALS ,SILICON ,ALUMINUM ,CRYSTALLIZATION ,EPITAXY ,THIN films ,SOLAR cells - Abstract
Polycrystalline silicon (pc-Si) thin-films with a grain size in the range of 0.1–100 μm grown on top of inexpensive substrates are economical materials for semiconductor devices such as transistors and solar cells and attract much attention nowadays. For pc-Si, grain size enlargement is thought to be an important parameter to improve material quality and therefore device performance. Aluminum-induced crystallization (AIC) of amorphous Si in combination with epitaxial growth allows achieving large-grained pc-Si layers on nonsilicon substrates. In this work, we made pc-Si layers with variable grain sizes by changing the crystallization temperature of the AIC process in order to see if larger grains indeed result in better solar cells. Solar cells based on these layers show a performance independent of the grain size. Defect etching and electron beam induced current (EBIC) measurements showed the presence of a high density of electrically active intragrain defects. We therefore consider them as the reason for the grain size independent device performance. Besides dislocations and stacking faults, also Σ3 boundaries were electrically active as shown by combining electron backscattered diffraction with EBIC measurements. The electrical activity of the defects is probably triggered by impurity decoration. Plasma hydrogenation changed the electrical behavior of the defects, as seen by photoluminescence, but the defects were not completely passivated as shown by EBIC measurements. In order to reveal the origin of the defects, cross section transmission electron microscopy measurements were done showing that the intragrain defects are already present in the AIC seed layer and get copied into the epitaxial layer during epitaxial growth. The same types of intragrain defects were found in layers made on different substrates (alumina ceramic, glass ceramic, and oxidized silicon wafer) from which we conclude that intragrain defects are not related to the relatively rough alumina ceramic substrates often used in combination with high temperature epitaxy. Further improvement of the material quality, and hence device performance, is therefore not simply achieved by increasing the grain size, but the intragrain quality of the material also needs to be taken into account. For pc-Si layers based on AIC and epitaxial growth, the seed layer has a crucial impact on the intragrain defect formation. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
3. Island growth in the atomic layer deposition of zirconium oxide and aluminum oxide on hydrogen-terminated silicon: Growth mode modeling and transmission electron microscopy.
- Author
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Puurunen, Riikka L., Vandervorst, Wilfried, Besling, Wim F. A., Richard, Olivier, Bender, Hugo, Conard, Thierry, Chao Zhao, Delabie, Annelies, Caymax, Matty, De Gendt, Stefan, Heyns, Marc, Viitanen, Minna M., de Ridder, Marco, Brongersma, Hidde H., Tamminga, Yde, Thuy Dao, de Win, Toon, Verheijen, Marcel, Kaiser, Monja, and Tuominen, Marko
- Subjects
SEMICONDUCTORS ,EPITAXY ,CRYSTAL growth ,ZIRCONIUM oxide ,SILICON ,ALUMINUM oxide ,ELECTRON microscopy - Abstract
Atomic layer deposition (ALD) is used in applications where inorganic material layers with uniform thickness down to the nanometer range are required. For such thicknesses, the growth mode, defining how the material is arranged on the surface during the growth, is of critical importance. In this work, the growth mode of the zirconium tetrachloride/water and the trimethyl aluminum/water ALD process on hydrogen-terminated silicon was investigated by combining information on the total amount of material deposited with information on the surface fraction of the material. The total amount of material deposited was measured by Rutherford backscattering, x-ray fluorescence, and inductively coupled plasma–optical emission spectroscopy, and the surface fractions by low-energy ion scattering. Growth mode modeling was made assuming two-dimensional growth or random deposition (RD), with a “shower model” of RD recently developed for ALD. Experimental surface fractions of the ALD-grown zirconium oxide and aluminum oxide films were lower than the surface fractions calculated assuming RD, suggesting the occurrence of island growth. Island growth was confirmed with transmission electron microscopy (TEM) measurements, from which the island size and number of islands per unit surface area could also be estimated. The conclusion of island growth for the aluminum oxide deposition on hydrogen-terminated silicon contradicts earlier observations. In this work, physical aluminum oxide islands were observed in TEM after 15 ALD reaction cycles. Earlier, thicker aluminum oxide layers have been analyzed, where islands have not been observed because they have already coalesced to form a continuous film. The unreactivity of hydrogen-terminated silicon surface towards the ALD reactants, except for reactive defect areas, is proposed as the origin of island growth. Consequently, island growth can be regarded as “undesired surface-selective ALD.” [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
4. TCAD Strain Calibration Versus Nanobeam Diffraction of Source/Drain Stressors for Ge MOSFETs.
- Author
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Buhler, Rudolf Theoderich, Eneman, Geert, Favia, Paola, Witters, Liesbeth Johanna, Vincent, Benjamin, Hikavyy, Andriy, Loo, Roger, Bender, Hugo, Collaert, Nadine, Simoen, Eddy, Martino, Joao Antonio, and Claeys, Cor
- Subjects
METAL oxide semiconductor field-effect transistors ,METAL oxide semiconductors ,SILICON compounds ,DIFFRACTION gratings ,SURFACE relief gratings - Abstract
TCAD finite-element process simulations have been performed on Ge-channel n and pMOSFETs with embedded source/drain stressors or a strained Ge channel on a relaxed SiGe strain relaxed buffer (SRB), respectively, and compared with nanobeam diffraction strain measurements. While there is overall a good agreement between the simulated and experimental strain profiles, some deviations may occur, due to the presence of extended defects in the strain relaxed Ge buffer layers. This highlights the importance of selection of a strain-free reference in the relaxed Ge or SiGe SRB. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
5. Selective Area Growth of InP and Defect Elimination on Si (001) Substrates.
- Author
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Gang Wang, Leys, Maarten, Loo, Roger, Richard, Olivier, Bender, Hugo, Brammertz, Guy, Waldron, Niamh, Wei-E Wang, Dekoster, Johan, Caymax, Matty, Seefeldt, Marc, and Heyns, Marc
- Subjects
SILICON ,GERMANIUM ,ATOMS ,GROUP 14 elements ,SEMIMETALS - Abstract
We report the selective area growth of InP layers in submicron trenches on Si (001) substrates by using a thin Ge buffer layer. The antiphase domain boundaries in InP layers are suppressed by engineering the local Ge surface profile. The mechanism of atomic step formation and the corresponding method for step density control are presented. We discuss the impact of the surface profile of the Ge buffer layer on the formation of antiphase domain boundaries as well as on InP nucleation. A minimum step density of 0.25 nm
-1 is required to avoid antiphase domain boundaries while a higher step density substantially reduces the stacking faults and twins in the InP nucleation layer. By employing the threading dislocation necking effect and the properly controlled Ge surface profile, high-quality InP layers have been obtained in submicron trenches. [ABSTRACT FROM AUTHOR]- Published
- 2011
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6. Germanium content dependence of the leakage current of recessed SiGe source/drain junctions.
- Author
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Simoen, Eddy, Bargallo Gonzalez, Mireia, Eneman, Geert, Verheyen, Peter, Benedetti, Aldo, Bender, Hugo, Loo, Roger, and Claeys, Cor
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GERMANIUM ,SILICON ,TRANSMISSION electron microscopy ,DENSITY ,ELECTRON microscopy - Abstract
The impact of the Ge fraction ( x), on the leakage current of recessed Si
1− x Gex p+ -n source/drain junctions has been investigated, for a fixed recess depth of 70 nm. It is found that both the bulk and the peripheral leakage current density increase approximately exponentially with increasing Ge content in the range 10–30%. Roughly speaking, the leakage current density increases one decade for every 5% increase in Ge. In case of the bulk leakage current density, this enhancement is shown to be related to the increase in extended defects penetrating the depletion region in the n-type silicon substrate. Transmission Electron Microscopy demonstrates a higher density of dislocations at the epitaxial interface for a higher Ge fraction, which are most likely generated by strain relaxation, induced by the implantation and activation of B in the p+ S/D regions. [ABSTRACT FROM AUTHOR]- Published
- 2007
- Full Text
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7. Strain mapping of tensiley strained silicon transistors with embedded Si1-yCy source and drain by dark-field holography.
- Author
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Hüe, Florian, Hÿtch, Martin, Houdellier, Florent, Bender, Hugo, and Claverie, Alain
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HOLOGRAPHY ,TRANSISTORS ,SILICON ,ELECTRON mobility ,TRANSMISSION electron microscopy ,FINITE element method - Abstract
Dark-field holography, a new transmission electron microscopy technique for mapping strain distributions at the nanoscale, is used to characterize strained-silicon n-type transistors with a channel width of 65 nm. The strain in the channel region, which enhances electron mobilities, is engineered by recessed Si
0.99 C0.01 source and drain stressors. The strain distribution is measured across an array of five transistors over a total area of 1.6 μm wide. The longitudinal tensile strain reaches a maximum of 0.58%±0.02% under the gate oxide. Theoretical strain maps obtained by finite element method agree well with the experimental results. [ABSTRACT FROM AUTHOR]- Published
- 2009
- Full Text
- View/download PDF
8. Growth mechanisms for Si epitaxy on O atomic layers: Impact of O-content and surface structure.
- Author
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Jayachandran, Suseendran, Billen, Arne, Douhard, Bastien, Conard, Thierry, Meersschaut, Johan, Moussa, Alain, Caymax, Matty, Bender, Hugo, Vandervorst, Wilfried, Heyns, Marc, and Delabie, Annelies
- Subjects
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SURFACE structure , *EPITAXY , *SILICON , *SUBSTRATES (Materials science) , *CRYSTAL defects , *OXYGEN , *CHEMICAL vapor deposition - Abstract
The epitaxial growth of Si layers on Si substrates in the presence of O atoms is generally considered a challenge, as O atoms degrade the epitaxial quality by generating defects. Here, we investigate the growth mechanisms for Si epitaxy on O atomic layers (ALs) with different O-contents and structures. O ALs are deposited by ozone (O 3 ) or oxygen (O 2 ) exposure on H-terminated Si at 50 °C and 300 °C respectively. Epitaxial Si is deposited by chemical vapor deposition using silane (SiH 4 ) at 500 °C. After O 3 exposure, the O atoms are uniformly distributed in Si-Si dimer/back bonds. This O layer still allows epitaxial seeding of Si. The epitaxial quality is enhanced by lowering the surface distortions due to O atoms and by decreasing the arrival rate of SiH 4 reactants, allowing more time for surface diffusion. After O 2 exposure, the O atoms are present in the form of SiO x clusters. Regions of hydrogen-terminated Si remain present between the SiO x clusters. The epitaxial seeding of Si in these structures is realized on H-Si regions, and an epitaxial layer grows by a lateral overgrowth mechanism. A breakdown in the epitaxial ordering occurs at a critical Si thickness, presumably by accumulation of surface roughness. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
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