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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.

Bordihn S.,Hanwha Q Cells GmbH | Bordihn S.,TU Eindhoven | Dingemans G.,TU Eindhoven | Mertens V.,Hanwha Q Cells GmbH | And 2 more authors.
IEEE Journal of Photovoltaics | Year: 2013

The surface passivation of SiO2/Al 2O3 stacks prepared at low process temperatures was investigated on phosphorous diffused n+-type Si surfaces with a broad range of sheet resistances. Two kinds of SiO 2 films were prepared, the first with plasma-enhanced chemical vapor deposition (PECVD) and the second in a wet chemical process. After atomic layer deposition of the Al 2O 3 capping layer, the resulting SiO2/Al 2O 3 stacks differ in the polarity of their fixed charge density, i.e., the PECVD SiO 2 stacks had a positive and the wet chemically grown SiO2 stacks a negative fixed charge density. The PECVD SiO 2/Al2O3 stacks resulted in a high surface passivation over a broad range of sheet resistances whereas the wet chemically grown SiO2 stacks were only feasible for diffused surfaces with low sheet resistances (< 100 Ω). By corona charging experiments, it was established that the field effect based on a negative fixed charge density was the reason for the loss in surface passivation in the specific range of diffused surfaces. © 2011-2012 IEEE.

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.

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.

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