Hugo Bender | IMEC - Academia.edu (original) (raw)

Papers by Hugo Bender

Applied Physics Letters, 1993

The formation and distribution of NiSi2 in (111) silicon by Ni-ion implantation with a fluence of... more The formation and distribution of NiSi2 in (111) silicon by Ni-ion implantation with a fluence of 1.1×1017 cm−2 and an energy of 90 keV is studied as a function of the temperature during implantation. For temperatures below 200 °C, a buried layer of NiSi2 precipitates is formed. Increasing the temperature gradually from 200 to 350 °C leads first to the formation of a double buried NiSi2 layer which with increasing temperature evolves into an epitaxial NiSi2 surface layer. A tentative model to explain for the observed anomalous behavior is presented.

MRS Proceedings, 1995

The results are discussed of the characterization by means of TEM, RBS and XRD of ErSi2_x layers ... more The results are discussed of the characterization by means of TEM, RBS and XRD of ErSi2_x layers prepared by ion beam synthesis on (111) silicon. It will be shown that high quality (buried) layers can be prepared by channelled implantation of the erbium, whereas unchannelled implantation leads to discontinuous polycrystalline surface layers. The epitaxial growth and vacancy ordering in the silicide are discussed.

Surface & Coatings Technology, Nov 1, 1996

Abstract In analogy to conventional beam-line ion implantation, plasma immersion ion implantation... more Abstract In analogy to conventional beam-line ion implantation, plasma immersion ion implantation can be combined with a deposition technique to an ion assisted coating process. The structure and composition of a coating and its interface to the substrate can be modified by ion implantation. By means of electron beam evaporation and oxygen plasma immersion ion implantation niobium oxide films were prepared at low substrate temperatures (

ECS Journal of Solid State Science and Technology, May 1, 2020

The deep levels in amorphous Ge 0.5 Se 0.5 layers have been analyzed by Deep Level Transient Spec... more The deep levels in amorphous Ge 0.5 Se 0.5 layers have been analyzed by Deep Level Transient Spectroscopy (DLTS). To that end, Metal-Insulator-Semiconductor (MIS) capacitors have been prepared by Physical Vapor Deposition of the films on p-type silicon substrates. A so-called quasi-constant capacitance procedure has been developed to account for the strong flat-band voltage shift of the capacitance-voltage characteristic with temperature. Applying this procedure to the as-deposited layers in the subthreshold regime reveals a dominant broad hole trap, with deep level parameters (trap concentration, hole capture cross section and activation energy) that strongly depend on the deposition conditions and the layer thickness. It is, finally, shown that the trap filling behavior does not follow the capture kinetics for simple point defects. Based on this observation, arguments are presented for an alternative analysis of the DLTS data.

Ultramicroscopy, 1989

A reproducible and rapid preparation technique for high-quality TEM specimens of semiconducting m... more A reproducible and rapid preparation technique for high-quality TEM specimens of semiconducting materials is reported. The required equipment is available in most laboratories working on TEM in the field of solid state materials (Disc Grinder, Dimple Grinder, Ion-Miller and Chemical. Thinning Equipment). Full cross-section preparation takes about 6 h. Plan view preparation takes between 2 and 5 h.

Proceedings, Oct 1, 2007

In this work, we investigate the possibility of achieving low VT nMOS FinFETs with single metal g... more In this work, we investigate the possibility of achieving low VT nMOS FinFETs with single metal gate by using a dysprosium oxide (Dy2O3) cap layer inserted between gate dielectric and metal. We determine an optimum ratio between Dy2O3 and SiO2 gate dielectric thicknesses for low nMOS VT with good process margin and no loss in performance and reliability.

Japanese Journal of Applied Physics, Apr 1, 2010

Leakage reduction is crucial for metal-insulator-metal (MIM) capacitors for future dynamic random... more Leakage reduction is crucial for metal-insulator-metal (MIM) capacitors for future dynamic random access memory (DRAM) nodes. In previous investigations we showed that increasing the Sr-content would result in leakage reduction of SrTiO 3 (STO) films deposited on TiN. 1,2) In this work we demonstrate for thin (10 nm) stoichiometric SrTiO 3 films that the leakage properties can be significantly lowered (while keeping high capacitance densities) by using stacking approaches such as seed layer (thin STO layer crystallized before the ''bulk'' STO deposition) and multistack SrTiO 3 /GdAlO 3 /SrTiO 3. In this work, SrTiO 3 films are deposited using a low temperature ALD process enabling the use of low-cost, manufacturable-friendly TiN-bottom electrode.

Journal of Materials Research, Dec 1, 2007

Ultrathin lanthanide (Nd, Pr, Eu, Sm) oxide films with functional dielectric properties down to 3... more Ultrathin lanthanide (Nd, Pr, Eu, Sm) oxide films with functional dielectric properties down to 3.3 nm thickness were deposited by aqueous chemical solution deposition (CSD) onto hydrophilic SiO2/Si substrates. Precursor solutions were prepared from the oxides via an intermediate, solid Ln(III)citrate. A film heat treatment scheme was derived from thermogravimetric analysis of the precursor gels, showing complete decomposition by 600 °C. Crystalline phase formation in the films depended on the lanthanide, annealing temperature, and citric acid content in the precursor. Through variation of the precursor concentration and number of deposited layers, thickness series of uniform films were obtained down to ∼3 nm. The film uniformity was demonstrated both by atomic force microscopy and cross-section transmission electron microscopy. The lanthanide oxide films possessed good dielectric properties. It was concluded that aqueous CSD allows deposition of uniform ultrathin films and may be useful for the evaluation of new high-k candidate materials.

Applied Physics Letters, Mar 17, 2008

The thermal stability of DyScO3 thin films in contact with SiO2 or HfO2 during annealing up to 10... more The thermal stability of DyScO3 thin films in contact with SiO2 or HfO2 during annealing up to 1000°C has been studied. It is found that DyScO3∕SiO2 stacks react during annealing and a phase separation into polycrystalline Sc-rich (and relatively Si-poor) DySc silicate on top of an amorphous Dy-rich DySc silicate is observed. In contrast, DyScO3 is found to be thermodynamically stable in contact with HfO2 and to recrystallize upon annealing. These results demonstrate that the previously reported high crystallization temperature of >1000°C for DyScO3 is not an intrinsic material property but caused by silicate formation.

ECS transactions, Dec 17, 2019

The lanthanide aluminates GdAlO3 and LuAlO3 have been examined for integration into advanced non-... more The lanthanide aluminates GdAlO3 and LuAlO3 have been examined for integration into advanced non-volatile memory devices. From a materials point of view, a number of physical properties of the material need to be understood prior to successful device integration, such as e.g. bandgap and band offsets, dielectric permittivity, or crystallization behavior. In addition to these material properties, the layers may have to withstand high thermal budgets during device processing such that thermal stability and interdiffusion in contact with surrounding materials become important.

Chemistry of Materials, May 31, 2017

Ruthenium thin films are deposited by atomic layer deposition (ALD) from bis(N,N'-di-tert-butylac... more Ruthenium thin films are deposited by atomic layer deposition (ALD) from bis(N,N'-di-tert-butylacetamidinato)ruthenium(II) dicarbonyl and O 2. Highly conductive, dense, and pure thin films can be deposited when oxygen exposure, E O , approaches a certain threshold (E max). When E O > E max the film peels off due to the recombinative desorption of O 2 at the film/substrate interface. Analysis by atomic probe microscopy (APM) shows that the crystallites are nearly free from carbon impurity (<0.1 at.-%), while a low level of carbon (<0.5 at.-%) is segregated near the grain boundaries. APM also shows that a small amount of O impurity (0.3 at.-%) is distributed uniformly between the crystallites and the grain boundaries.

Chemical Communications, 2015

We demonstrate the impact of reducing agents for Chemical Vapor Deposition (CVD) and Atomic Layer... more We demonstrate the impact of reducing agents for Chemical Vapor Deposition (CVD) and Atomic Layer Deposition (ALD) of WS 2 from WF 6 and H 2 S precursors. Nanocrystalline WS 2 layers with a twodimensional structure can be obtained at low deposition temperatures (300-450 8C) without using a template or anneal.

ECS Journal of Solid State Science and Technology, Nov 30, 2012

The atomic layer deposition of titanium oxide TiO 2 on ruthenium and oxidized ruthenium with tita... more The atomic layer deposition of titanium oxide TiO 2 on ruthenium and oxidized ruthenium with titanium methoxide as metal precursor and H 2 O and O 3 as oxidant was investigated by Rutherford backscattering (RBS) and time of flight secondary ion mass spectrometry (TOFSIMS). An ultra-thin layer of TiO 2 deposited a priori with H 2 O plays the role of protection of Ru(O x) substrates against etching by O 3. Information about thin films (∼3 nm) interfacial reactions, thickness and structure was brought by Medium Energy Ion Scattering Spectroscopy (MEIS) and X-ray absorption spectroscopy (XAS) measurements. The growth enhancements observed in the first stages of the deposition depends on the pre-treatment (pre-oxidation, H 2 O based interlayer thickness) of the Ru substrate. Thick films (∼14 nm) were analyzed by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The as deposited TiO 2 films are crystalline with rutile structure, as resulted from structural analyzes. However, the presence of small amounts of anatase was detected by soft X-ray absorption spectroscopy (XAS) and is strongly influenced by the surface pre-treatment of the Ru substrate. The electrical properties (equivalent oxide thickness and leakage current density) correlate with a different rutile/anatase ratio present in the films.

Chemistry of Materials, Mar 16, 2017

Two-dimensional (2D) transition metal dichalcogenides are potential low dissipative semiconductor... more Two-dimensional (2D) transition metal dichalcogenides are potential low dissipative semiconductor materials for nanoelectronic devices. Such applications require the deposition of these materials in their crystalline form and with controlled number of monolayers on large area substrates, preferably using growth temperatures compatible with temperature sensitive structures. This paper presents a low temperature Plasma Enhanced Atomic Layer Deposition (PEALD) process for 2D WS2 based on a ternary reaction cycle consisting of consecutive WF6, H2 plasma and H2S reactions. Strongly textured nanocrystalline WS2 is grown at 300 °C. The composition and crystallinity of these layers depends on the PEALD process conditions, as understood by a model for the redox chemistry of this process. The H2 plasma is essential for the deposition of WS2 as it enables the reduction of-W 6+ Fx surface species. Nevertheless, the impact of sub-surface reduction reactions needs to be minimized to obtain WS2 with well-controlled composition (S/W ratio of two).

$Research paper thumbnail of Diffraction studies for stoichiometry effects in BaTiO3grown by molecular beam epitaxy on Ge(001)$

Journal of Applied Physics, Dec 14, 2016

In this work, we present a systematic study of the effect of the stoichiometry of BaTiO 3 (BTO) f... more In this work, we present a systematic study of the effect of the stoichiometry of BaTiO 3 (BTO) films grown on the Ge(001) substrate by molecular-beam-epitaxy using different characterization methods relying on beam diffraction, including reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD), and selected-area electron diffraction in transmission electron microscopy. Surprisingly, over a wide range of [Ba]/[Ti] ratios, as measured by the Rutherford backscattering spectrometry, all the BTO layers exhibit the same epitaxial relationship h100iBTO(001)// h110iGe(001) with the substrate, describing a 45 lattice rotation of the BTO lattice with respect to the Ge lattice. However, varying the [Ba]/[Ti] ratio does change the diffraction behavior. From RHEED patterns, we can derive that excessive [Ba] and [Ti] generate twinning planes and a rougher surface in the non-stoichiometric BTO layers. XRD allows us to follow the evolution of the lattice constants as a function of the [Ba]/[Ti] ratio, providing an option for tuning the tetragonality of the BTO layer. In addition, we found that the intensity ratio of the 3 lowest-order Bragg peaks I (001) / I (002) , I (101) /I (002), and I (111) /I (002) derived from x À 2h scans characteristically depend on the BTO stoichiometry. To explain the relation between observed diffraction patterns and the stoichiometry of the BTO films, we propose a model based on diffraction theory explaining how excess [Ba] or [Ti] in the layer influences the diffraction response. Published by AIP Publishing.

Microelectronic Engineering, May 1, 2014

With the downscaling of the interconnect technology, the resistance of industry standard Cu incre... more With the downscaling of the interconnect technology, the resistance of industry standard Cu increases for the sub-20 lines due to the increased grain boundary and surface scattering. With the reduction of the geometry sizes and increase of aspect ratios, the ability to achieve a uniform Cu metallization becomes challenging. Hence, interests on low resistive alternative metals or alloy thin films deposited with good trench filling capability technologies becomes increasingly important. In this context, in the present study, an unconventional route is explored to synthesize Cu 3 Ge films via CVD of GeH 4 gas with thin solid Cu films at BEOL compatible temperatures (250°C). Results show that e 1-Cu 3 Ge films could be successfully grown on 300 mm blanket and on patterned wafers by exposing GeH 4 precursors over Cu films at 250°C. The GeH 4 CVD conditions were optimized, on different thicknesses of Cu, to grow phase pure and stoichiometric low resistive Cu 3 Ge layers on blanket wafers. In-situ XRD analyses combined with anneal studies show that the Cu 3 Ge films are thermally stable up to 600°C with no signs of decomposition. Our investigation was further extended to the growth of Cu 3 Ge in trenches and showed that the GeH 4 decomposition-cum-reaction with Cu is uniform along the trench depth, completely transforming the Cu to Cu 3 Ge films with a limited volume expansion, as evidenced by the GIXRD, SEM and TEM analysis.

Journal of vacuum science and technology, 2011

Strontium titanate ͑STO͒ is a dielectric with a cubic perovskite type structure and of increasing... more Strontium titanate ͑STO͒ is a dielectric with a cubic perovskite type structure and of increasing interest for microelectronics, especially in the metal-insulator-metal ͑MIM͒ capacitors due to its high dielectric constant. The dielectric constant of the STO films and consequently the performance of the MIM capacitors appear to be strongly influenced by the process conditions. In this work the authors report on the influence of various thermal treatments upon the crystallinity and morphology of strontium titanate crystals. The influence of spike, laser, or rapid thermal anneals on the morphology with respect to grain size and topography of the crystalline stoichiometric STO films is studied. Also, the use of a stack containing a Sr-rich STO ͑62% Sr͒ bottom seed layer and a stoichiometric STO top layer in combination with a thermal treatment was found to affect the microstructure of the STO film. A comparison of the electrical properties for various thermal treatments has been made.