Atomic layer deposition (ALD) is a widely recognized technique for depositing ultrathin conformal... more Atomic layer deposition (ALD) is a widely recognized technique for depositing ultrathin conformal films with excellent thickness control at Ångström or (sub)monolayer level. Atmospheric-pressure ALD is an upcoming ALD process with a potentially lower ownership cost of the reactor. In this review, we provide a comprehensive overview of the recent applications and development of ALD approaches emphasizing those based on operation at atmospheric pressure. Each application determines its own specific reactor design. Spatial ALD (s-ALD) has been recently introduced for the commercial production of large-area 2D displays, the surface passivation and encapsulation of solar cells and organic light-emitting diode (OLED) displays. Atmospheric temporal ALD (t-ALD) has opened up new emerging applications such as high-porosity particle coatings, functionalization of capillary columns for gas chromatography, and membrane modification in water treatment and gas purification. The challenges and opportunities for highly conformal coating on porous substrates by atmospheric ALD have been identified. We discuss in particular the pros and cons of both s-ALD and t-ALD in combination with their reactor designs in relation to the coating of 3D and highporosity materials.
2007 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems
... integrate. Inductors are made by using the two metal layers also used for interconnects. ... ... more ... integrate. Inductors are made by using the two metal layers also used for interconnects. ... checks. Finally, this IC-like Design Environment has contributed a lot to the adoption ofthe technology. V. INNOVATIVE TESTING SOLUTIONS ...
We present independently confirmed efficiencies of 21.4% for PERC cells with plasma-assisted atom... more We present independently confirmed efficiencies of 21.4% for PERC cells with plasma-assisted atom-ic-layer-deposited (plasma ALD) Al2O3 rear passivation and 20.7% for cells with thermal ALD-Al2O3. Additionally, we evaluate three different industrially relevant techniques for the deposition of surface-passivating Al2O3 layers on 1-cm p-type silicon wafers, namely high-rate spatial ALD (spatial ALD), plasma-enhanced chemical vapour deposi-tion (PECVD) and reactive sputtering. Using spatial ALD and PECVD, surface recombination velocities (SRVs) be-low 10 cm/s are obtained. Sputtered Al2O3 layers still provide an SRV of 35 – 70 cm/s. Despite their lower passiva-tion quality compared to the Al2O3 films deposited by spatial ALD and by PECVD, we demonstrate that the sputtered Al2O3 layers are still suitable for the fabrication of 20.1% efficient PERC cells. After firing at ~800°C in a conveyor-belt furnace the SRV provided by the Al2O3 films deposited by spatial ALD is still below 20 cm/s,...
Area-selective atomic layer deposition (ALD) of ZnO was achieved on SiO 2 seed layer patterns on ... more Area-selective atomic layer deposition (ALD) of ZnO was achieved on SiO 2 seed layer patterns on Hterminated silicon substrates, using diethylzinc (DEZ) as the zinc precursor and H 2 O as the coreactant. The selectivity of the ALD process was studied using in situ spectroscopic ellipsometry and scanning electron microscopy, revealing improved selectivity for increasing deposition temperatures from 100 to 300°C. The selectivity was also investigated using transmission electron microscopy and energy-dispersive X-ray spectroscopy. Density functional theory (DFT) calculations were performed to corroborate the experimental results obtained and to provide an atomic-level understanding of the underlying surface chemistry. A kinetically hindered proton transfer reaction from the H-terminated Si was conceived to underpin the selectivity exhibited by the ALD process. By combining the experimental and DFT results, we suggest that the trend in selectivity with temperature may be due to a strong DEZ or H 2 O physisorption on the H-terminated Si that hampers high selectivity at low deposition temperature. This work highlights the deposition temperature as an extra process parameter to improve the selectivity.
DOI to the publisher's website. • The final author version and the galley proof are versions of t... more DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:
Chemistry of materials : a publication of the American Chemical Society, Jan 27, 2018
The maximum conductivity achievable in Al-doped ZnO thin films prepared by atomic layer depositio... more The maximum conductivity achievable in Al-doped ZnO thin films prepared by atomic layer deposition (ALD) is limited by the low doping efficiency of Al. To better understand the limiting factors for the doping efficiency, the three-dimensional distribution of Al atoms in the ZnO host material matrix has been examined on the atomic scale using a combination of high-resolution transmission electron microscopy (TEM) and atom probe tomography (APT). Although the Al distribution in ZnO films prepared by so-called "ALD supercycles" is often presented as atomically flat δ-doped layers, in reality a broadening of the Al-dopant layers is observed with a full-width-half-maximum of ∼2 nm. In addition, an enrichment of the Al at grain boundaries is observed. The low doping efficiency for local Al densities > ∼1 nm can be ascribed to the Al solubility limit in ZnO and to the suppression of the ionization of Al dopants from adjacent Al donors.
Atomic layer deposition (ALD) is a technique that uses a cyclical exposure and purging of chemica... more Atomic layer deposition (ALD) is a technique that uses a cyclical exposure and purging of chemical precursors to create thin films. ALD offers a high degree of control over the thickness and composition of the films. The technique is generally used for binary compounds such as oxide and nitrides. ZnO is grown by ALD as a transparent conductive oxide for photovoltaic and optoelectronic applications.
Materials Science in Semiconductor Processing, 1999
... it eliminates the actual number of free interstitials as a parameter in the problem, and allo... more ... it eliminates the actual number of free interstitials as a parameter in the problem, and allows us to write down an ... I +Q V =4.75 eV recently found for the total self-diffusion coefficient [22], our result supports Ural's conclusion [21] that ... The extracted values of E diss are plotted in Fig ...
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, 2004
The effect of preamorphization and solid-phase epitaxial regrowth on indium doping profiles in si... more The effect of preamorphization and solid-phase epitaxial regrowth on indium doping profiles in silicon has been investigated. It is shown that preamorphized silicon significantly reduces channeling during indium ion implantation, producing a much more abrupt doping profile. During recrystallization by thermal annealing, indium segregates in front of the moving amorphous/crystalline interface, creating a clearly visible peak in the doping profile. We establish that the physical mechanism for this phenomenon in the 1018–1019 cm−3 concentration range is segregation determined, as there is no significant concentration dependence for those doses studied in this work. We also demonstrate that this phenomenon is enhanced at lower temperatures.
Atomic layer deposition (ALD) is a widely recognized technique for depositing ultrathin conformal... more Atomic layer deposition (ALD) is a widely recognized technique for depositing ultrathin conformal films with excellent thickness control at Ångström or (sub)monolayer level. Atmospheric-pressure ALD is an upcoming ALD process with a potentially lower ownership cost of the reactor. In this review, we provide a comprehensive overview of the recent applications and development of ALD approaches emphasizing those based on operation at atmospheric pressure. Each application determines its own specific reactor design. Spatial ALD (s-ALD) has been recently introduced for the commercial production of large-area 2D displays, the surface passivation and encapsulation of solar cells and organic light-emitting diode (OLED) displays. Atmospheric temporal ALD (t-ALD) has opened up new emerging applications such as high-porosity particle coatings, functionalization of capillary columns for gas chromatography, and membrane modification in water treatment and gas purification. The challenges and opportunities for highly conformal coating on porous substrates by atmospheric ALD have been identified. We discuss in particular the pros and cons of both s-ALD and t-ALD in combination with their reactor designs in relation to the coating of 3D and highporosity materials.
2007 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems
... integrate. Inductors are made by using the two metal layers also used for interconnects. ... ... more ... integrate. Inductors are made by using the two metal layers also used for interconnects. ... checks. Finally, this IC-like Design Environment has contributed a lot to the adoption ofthe technology. V. INNOVATIVE TESTING SOLUTIONS ...
We present independently confirmed efficiencies of 21.4% for PERC cells with plasma-assisted atom... more We present independently confirmed efficiencies of 21.4% for PERC cells with plasma-assisted atom-ic-layer-deposited (plasma ALD) Al2O3 rear passivation and 20.7% for cells with thermal ALD-Al2O3. Additionally, we evaluate three different industrially relevant techniques for the deposition of surface-passivating Al2O3 layers on 1-cm p-type silicon wafers, namely high-rate spatial ALD (spatial ALD), plasma-enhanced chemical vapour deposi-tion (PECVD) and reactive sputtering. Using spatial ALD and PECVD, surface recombination velocities (SRVs) be-low 10 cm/s are obtained. Sputtered Al2O3 layers still provide an SRV of 35 – 70 cm/s. Despite their lower passiva-tion quality compared to the Al2O3 films deposited by spatial ALD and by PECVD, we demonstrate that the sputtered Al2O3 layers are still suitable for the fabrication of 20.1% efficient PERC cells. After firing at ~800°C in a conveyor-belt furnace the SRV provided by the Al2O3 films deposited by spatial ALD is still below 20 cm/s,...
Area-selective atomic layer deposition (ALD) of ZnO was achieved on SiO 2 seed layer patterns on ... more Area-selective atomic layer deposition (ALD) of ZnO was achieved on SiO 2 seed layer patterns on Hterminated silicon substrates, using diethylzinc (DEZ) as the zinc precursor and H 2 O as the coreactant. The selectivity of the ALD process was studied using in situ spectroscopic ellipsometry and scanning electron microscopy, revealing improved selectivity for increasing deposition temperatures from 100 to 300°C. The selectivity was also investigated using transmission electron microscopy and energy-dispersive X-ray spectroscopy. Density functional theory (DFT) calculations were performed to corroborate the experimental results obtained and to provide an atomic-level understanding of the underlying surface chemistry. A kinetically hindered proton transfer reaction from the H-terminated Si was conceived to underpin the selectivity exhibited by the ALD process. By combining the experimental and DFT results, we suggest that the trend in selectivity with temperature may be due to a strong DEZ or H 2 O physisorption on the H-terminated Si that hampers high selectivity at low deposition temperature. This work highlights the deposition temperature as an extra process parameter to improve the selectivity.
DOI to the publisher's website. • The final author version and the galley proof are versions of t... more DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:
Chemistry of materials : a publication of the American Chemical Society, Jan 27, 2018
The maximum conductivity achievable in Al-doped ZnO thin films prepared by atomic layer depositio... more The maximum conductivity achievable in Al-doped ZnO thin films prepared by atomic layer deposition (ALD) is limited by the low doping efficiency of Al. To better understand the limiting factors for the doping efficiency, the three-dimensional distribution of Al atoms in the ZnO host material matrix has been examined on the atomic scale using a combination of high-resolution transmission electron microscopy (TEM) and atom probe tomography (APT). Although the Al distribution in ZnO films prepared by so-called "ALD supercycles" is often presented as atomically flat δ-doped layers, in reality a broadening of the Al-dopant layers is observed with a full-width-half-maximum of ∼2 nm. In addition, an enrichment of the Al at grain boundaries is observed. The low doping efficiency for local Al densities > ∼1 nm can be ascribed to the Al solubility limit in ZnO and to the suppression of the ionization of Al dopants from adjacent Al donors.
Atomic layer deposition (ALD) is a technique that uses a cyclical exposure and purging of chemica... more Atomic layer deposition (ALD) is a technique that uses a cyclical exposure and purging of chemical precursors to create thin films. ALD offers a high degree of control over the thickness and composition of the films. The technique is generally used for binary compounds such as oxide and nitrides. ZnO is grown by ALD as a transparent conductive oxide for photovoltaic and optoelectronic applications.
Materials Science in Semiconductor Processing, 1999
... it eliminates the actual number of free interstitials as a parameter in the problem, and allo... more ... it eliminates the actual number of free interstitials as a parameter in the problem, and allows us to write down an ... I +Q V =4.75 eV recently found for the total self-diffusion coefficient [22], our result supports Ural's conclusion [21] that ... The extracted values of E diss are plotted in Fig ...
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, 2004
The effect of preamorphization and solid-phase epitaxial regrowth on indium doping profiles in si... more The effect of preamorphization and solid-phase epitaxial regrowth on indium doping profiles in silicon has been investigated. It is shown that preamorphized silicon significantly reduces channeling during indium ion implantation, producing a much more abrupt doping profile. During recrystallization by thermal annealing, indium segregates in front of the moving amorphous/crystalline interface, creating a clearly visible peak in the doping profile. We establish that the physical mechanism for this phenomenon in the 1018–1019 cm−3 concentration range is segregation determined, as there is no significant concentration dependence for those doses studied in this work. We also demonstrate that this phenomenon is enhanced at lower temperatures.
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