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Perez E.,Ihp Microelectronics | Grossi A.,University of Ferrara | Zambelli C.,University of Ferrara | Olivo P.,University of Ferrara | And 2 more authors.
IEEE Electron Device Letters | Year: 2017

In this letter, we propose an effective route to reduce the cell-to-cell variability in 1T-1R-based random access memories (RRAM) arrays by combining the excellent switching performance of Hf1-xAlxOy with an optimized incremental step pulse with verify algorithm for programming. The strongly reduced cell-to-cell variability improves the thermal and post-programming stability of the arrays, which is relevant for many applications of the RRAM technology. Finally, the retention study at 150 °C enables the prediction of the data storage capability. © 1980-2012 IEEE.


Marsik P.,Masaryk University | Marsik P.,IMEC | Urbanowicz A.M.,Masaryk University | Verdonck P.,IMEC | And 3 more authors.
Thin Solid Films | Year: 2011

A set of SiCOH low dielectric constant films (low-k) has been deposited by plasma enhanced chemical vapor deposition using variable flow rates of the porogen (sacrificial phase) and matrix precursors. During the deposition, two different substrate temperatures and radio frequency power settings were applied. Next, the deposited films were cured by the UV assisted annealing (UV-cure) using two industrial UV light sources: a monochromatic UV source with intensity maximum at λ = 172 nm (lamp A) and a broadband UV source with intensity spectrum distributed below 200 nm (lamp B). This set of various low-k films has been additionally exposed to NH3 plasma (used for the CuOx reduction during Cu/low-k integration) in order to evaluate the effect of the film preparation conditions on the plasma damage resistance of low-k material. Results show that the choice of the UV-curing light source has significant impact on the chemical composition of the low-k material and modifies the porogen removal efficiency and subsequently the material porosity. The 172 nm photons from lamp A induce greater changes to most of the evaluated properties, particularly causing undesired removal of SiCH3 groups and their replacement with SiH. The softer broadband radiation from lamp B improves the porogen removal efficiency, leaving less porogen residues detected by spectroscopic ellipsometry in UV range. Furthermore, it was found that the degree of bulk hydrophilization (plasma damage) after NH3 plasma exposure is driven mainly by the film porosity. © 2011 Elsevier B.V. All rights reserved.


Marsik P.,Masaryk University | Marsik P.,IMEC | Verdonck P.,IMEC | De Roest D.,ASM Belgium | Baklanov M.R.,IMEC
Thin Solid Films | Year: 2010

The optical properties of low dielectric constant (low-k) films have been determined by variable angle spectroscopic ellipsometry in the range from 2 eV to 9 eV to characterize the process of porogen removal during the UV-cure. The studied carbon doped oxide (SiCOH) porous dielectric films have been prepared by plasma enhanced chemical vapor deposition. The films have been deposited as a composition of a matrix precursor and an organic porogen. After deposition, the films have been cured by thermal annealing and UV irradiation (λ = 172 nm) to remove the porogen and create a porosity of 33%, reaching a dielectric constant of 2.3. The process of porogen decomposition and removal has been studied on series of low-k samples, UV-cured for various times. Additional samples have been prepared by the deposition and curing of the porogen film, without SiCOH matrix, and the matrix material itself, without porogen. The analysis of the optical response of the porous dielectric as a mixture of matrix material, porogen and voids, together with Fourier transform infrared analysis, allows the sensitive detection of the volume of the porogen and indicates the existence of decomposed porogen residues inside the pores, even for long curing time. The variation of the deposition and curing conditions can control the amount of the porogen residues and the final porosity. © 2010 Elsevier B.V. All rights reserved.


Jung S.-H.,ASM Microchemistry Oy | Raisanen P.I.,ASM Microchemistry Oy | Givens M.E.,ASM Microchemistry Oy | Shero E.J.,ASM Microchemistry Oy | And 4 more authors.
ECS Transactions | Year: 2010

Optimization of the O2/N2 feed gas flow during O 3 generation by dielectric barrier discharge was found to improve the growth rate and uniformity of HfO2 and La2O3 films by atomic layer deposition (ALD) in a hot wall cross-flow thermal ALD reactor. Discharge products from the O3 generator and from the exhaust of the ALD reactor were analyzed by FTIR spectrometry. N2O, N2O5, NO2 and NO species were detected, as well as unreacted O3. Alternate models which could explain the behavior of various ozone-based ALD processes utilizing N2 doped O3 generation are presented. ©The Electrochemical Society.


Givens M.,ASM Microchemistry Oy | Tang F.,ASM Microchemistry Oy | Xie Q.,ASM Belgium | Maes J.W.,ASM Belgium
ECS Transactions | Year: 2015

III-V compound semiconductors are promising transistor channel materials to enable scaling beyond Si technology due to their high bulk electron mobility values. Engineering the III-V / high-k gate stack remains one of the main technical challenges to integration of these materials in CMOS technology, with Atomic Layer Deposition (ALD) continuing to play an enabling role. In this work, multiple approaches for interfacial sulfur passivation prior to highk gate stack deposition are explored, with passivated samples exhibiting improved C-V characteristics and reduced Dit values for planar MOSCAPS. Various III-V channel / high-k metal oxide interface layers (ILs) deposited by ALD have also been evaluated in order to reduce the impact of oxide traps while also maintaining a low Dit. A novel ALD interfacial layer material has been developed which demonstrates the potential to meet challenging requirements for III-V channel transistor integration. © The Electrochemical Society.


Delabie A.,IMEC | Caymax M.,IMEC | Gielis S.,IMEC | Maes J.W.,ASM Belgium | And 6 more authors.
Electrochemical and Solid-State Letters | Year: 2010

The O2 / N2 flow ratio during O3 generation by dielectric barrier discharge has a large impact on the atomic layer deposition (ALD) of metal oxides in a hot wall ALD reactor. For HfO 2 ALD using HfCl4 as a metal precursor, a higher growth per cycle and a broader ALD temperature window are obtained when N2 is added to the O2 supply of the O3 generation. A positive impact of N2 in the O3 generation is also observed for ZrO2 and La2 O3 ALD. A negative impact is observed for Al2 O3 ALD: The Al2 O3 thickness is reduced for those conditions for O3 where HfO 2 ALD is enhanced. © 2010 The Electrochemical Society.


Swerts J.,IMEC | Peys N.,IMEC | Peys N.,Catholic University of Leuven | Nyns L.,IMEC | And 6 more authors.
Journal of the Electrochemical Society | Year: 2010

The downscaling of high- κ/metal gate transistor devices requires thin-film deposition processes that deliver not only an outstanding high- k oxide quality, but also a strict interfacial oxide thickness control in the sub-1 nm thickness range. To study the impact of atomic layer deposition (ALD) process conditions and chemistry on the HfO2 quality and interfacial oxide thickness, we have used tetrakis[ethylmethylamino]hafnium (TEMAH) as a metal precursor and H2O and O3 as oxidants. The deposition temperature ranged from 285 up to 365°C, where TEMAH decomposition plays a role in the growth mechanism. Physical characterization and Pt dot capacitor devices have been used to study the impact of the oxidant and process conditions on the equivalent oxide thickness and gate leakage current of 2-4 nm thin HfO2 films. By combining X-ray reflectometry and ellipsometry, we evaluated the Si/high- κ interfacial oxide layer thickness. Time-of-flight secondary-ion mass spectroscopy was used to determine the C impurity levels. Both the interfacial oxide layer thickness and the C impurity level in the Si/ SiO2/HfO2 stacks are strongly dependent on the oxidant. The temperature dependence of the C impurity level is opposite for O3 and H2O. Furthermore, SiO2 regrowth was found for the O3 process. © 2009 The Electrochemical Society.


Dingemans G.,TU Eindhoven | Terlinden N.M.,TU Eindhoven | Pierreux D.,ASM Belgium | Profijt H.B.,TU Eindhoven | And 2 more authors.
Electrochemical and Solid-State Letters | Year: 2011

Differences in Si surface passivation by aluminum oxide (Al2 O3) films synthesized using H2 O and O3 -based thermal atomic layer deposition (ALD) and plasma ALD have been revealed. A low interface defect density of Dit =∼ 1011 eV-1 cm-2 was obtained after annealing, independent of the oxidant. This low Dit was found to be vital for the passivation performance. Field-effect passivation was less prominent for H2 O -based ALD Al2 O3 before and after annealing, whereas for as-deposited ALD films with an O2 plasma or O3 as the oxidants, the field-effect passivation was impaired by a very high Dit. © 2010 The Electrochemical Society.


Adelmann C.,IMEC | Tielens H.,IMEC | Dewulf D.,Hasselt University | Dewulf D.,IMEC | And 10 more authors.
Journal of the Electrochemical Society | Year: 2010

Gdx Hf1-x Oy thin films were deposited by atomic layer deposition (ALD) using tris(isopropyl-cyclopentadienyl) gadolinium [Gd (iPi rCp) 3] and HfCl4 in combination with H2 O as an oxidizer. Growth curves showed a nearly ideal ALD behavior. The growth per individual Gd (Pi rCp)3 / H2 O or HfCl4 / H2 O cycle was 0.55 Å, independent of the Gd/ (Gd+Hf) composition x in the studied range. This indicates that the amount of HfO2 deposited during a HfCl4 / H2 O cycle was essentially identical to the amount of Gd2 O3 deposited during a Gd (Pi rCp) 3 / H2 O cycle, assuming identical atomic densities of the films independent of composition. The crystallization of Gdx Hf1-x Oy with Gd/ (Gd+Hf) contents x between 7 and 30% was studied. Films with x10% crystallized into a cubic/tetragonal HfO2 -like phase during spike or laser annealing up to 1300°C, demonstrating that the cubic/tetragonal phase is thermally stable in this temperature range. A maximum dielectric constant of κ∼36 was found for a Gd/ (Gd+Hf) concentration of x∼11%. © 2010 The Electrochemical Society.


Tomasini P.,ASM Microchemistry Oy | Machkaoutsan V.,ASM Belgium | Thomas S.G.,ASM Microchemistry Oy
Thin Solid Films | Year: 2010

An empirical study of the selective vapor phase epitaxy kinetics of silicon germanium (Si1 - xGex) alloys is developed with no assumption on an atomistic mechanism. The growth kinetics are approached efficiently with a power rate law. Partial reaction orders are identified for GeH4, HCl and B2H6 precursors. A trend analysis of the partial reaction order highlights the fine characteristics of the Si1 - xGex growth kinetics. The power rate law evidences clearly the competition interactions between Si, Ge and B. Furthermore, a partial derivative study of the power rate law enabled an accurate sensitivity analysis of the selective process. © 2009 Elsevier B.V. All rights reserved.

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