Effect of ozone concentration on silicon surface passivation by atomic layer deposited Al2O3

Gastrow, Guillaume von; Li, Shuo; Putkonen, Matti; Laitinen, Mikko; Sajavaara, Timo; Savin, Hele

doi:10.1016/j.apsusc.2015.09.263

Cited by 19 publications

(16 citation statements)

References 28 publications

(30 reference statements)

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“…This is in agreement with earlier reported TMA-ozone ALD Al 2 O 3 films, in which ozone lead to higher C content than corresponding TMA-water process, 1 at% as compared with 0.2 at%, respectively. [37] The results are also indirectly supported by ellipsometer and X-ray reflectivity (XRR) measurements, i.e., the measured RI (1.57) and film mass density (2.8 g cm −3 ) are lower with ozone process than with water process (1.60 and 3.0 g cm −3 , respectively). The higher amount of film impurities indicates that the reaction between DMACl and ozone is less complete than DMACl-water reaction when the same deposition conditions are applied.…”

Section: Ozone Versus Water In Dmacl-based Al 2 O 3 Processsupporting

confidence: 60%

Ozone‐Based Atomic Layer Deposition of Al₂O₃ from Dimethylaluminum Chloride and Its Impact on Silicon Surface Passivation

Bao

Laitinen

Sajavaara

et al. 2017

Adv Elect Materials

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Dimethylaluminum chloride (DMACl) as an aluminum source has shown promising potential to replace more expensive and commonly used trimethylaluminum in the semiconductor industry for atomic layer deposited (ALD) thin films. Here, the Al2O3 DMACl‐process is modified by replacing the common ALD oxidant, water, by ozone that offers several benefits including shorter purge time, layer‐by‐layer growth, and improved film adhesion. It is shown that the introduction of the ozone instead of water increases carbon and chlorine content in the Al2O3, while long ozone pulses increase the amount of interfacial hydrogen at silicon surface. These are found to be beneficial effects regarding the surface passivation and thus final device operation. Heat treatments (at 400 and 800 °C) are found to be essential for high quality surface passivation similar to ALD Al2O3 deposited from conventional precursors, which is correlated with the changes at the interface and related impurity distributions. The optimal deposition temperature is found to be 250 °C, which provides the best chemical passivation after thermal treatments.

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Section: Ozone Versus Water In Dmacl-based Al 2 O 3 Processsupporting

confidence: 60%

Ozone‐Based Atomic Layer Deposition of Al₂O₃ from Dimethylaluminum Chloride and Its Impact on Silicon Surface Passivation

Bao

Laitinen

Sajavaara

et al. 2017

Adv Elect Materials

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“…Thermal SiO 2 was grown during implantation anneal, and 20 nm of Al 2 O 3 was deposited by thermal atomic layer deposition (ALD) at 200 C from trimethylaluminium and a combination of water and ozone at a concentration of 162 g/m 3 . 30 The thermal oxide was removed in sample SRV4 in a BHF solution before ALD. In samples SRV1 and SRV3, Al 2 O 3 was grown directly on top of thermal SiO 2 .…”

Section: Methodsmentioning

confidence: 99%

Recombination processes in passivated boron-implanted black silicon emitters

Gastrow

Ortega

Alcubilla

et al. 2017

Journal of Applied Physics

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Recombination processes in passivated boron-implanted black silicon emitters In this paper, we study the recombination mechanisms in ion-implanted black silicon (bSi) emitters and discuss their advantages over diffused emitters. In the case of diffusion, the large bSi surface area increases emitter doping and consequently Auger recombination compared to a planar surface. The total doping dose is on the contrary independent of the surface area in implanted emitters, and as a result, we show that ion implantation allows control of emitter doping without compromise in the surface aspect ratio. The possibility to control surface doping via implantation anneal becomes highly advantageous in bSi emitters, where surface passivation becomes critical due to the increased surface area. We extract fundamental surface recombination velocities S n through numerical simulations and obtain the lowest values at the highest anneal temperatures. With these conditions, an excellent emitter saturation current (J 0e ) is obtained in implanted bSi emitters, reaching 20 fA/cm 2 6 5 fA/cm 2 at a sheet resistance of 170 X/sq. Finally, we identify the different regimes of recombination in planar and bSi emitters as a function of implantation anneal temperature. Based on experimental data and numerical simulations, we show that surface recombination can be reduced to a negligible contribution in implanted bSi emitters, which explains the low J 0e obtained. Published by AIP Publishing. [http://dx

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“…The thickness of the Al 2 O 3 film was ≈22 nm, and the passivation layer was annealed in a nitrogen atmosphere at 400 °C for 30 min to activate the passivation, resulting in a surface recombination velocity of ≈7 cm s −1 . [45] The minority carrier lifetimes of all samples were characterized with microwave-assisted Photoconductance Decay (µ-PCD) method using Semilab WT-85 scanner with a 905 nm excitation laser, 200 ns pulse length, 1 mm 2 pulse spot size, and 1.2 × 10 13 photons per pulse. The interstitial iron concentration was calculated by the change in lifetime before and after the dissociation of Fe-B pairs by illumination.…”

Section: Methodsmentioning

confidence: 99%

“…Subsequently, the wafer surface was passivated by ALD Al 2 O 3 . The thickness of the Al 2 O 3 film was ≈22 nm, and the passivation layer was annealed in a nitrogen atmosphere at 400 °C for 30 min to activate the passivation, resulting in a surface recombination velocity of ≈7 cm s −1 …”

Section: Methodsmentioning

confidence: 99%

Electronic Quality Improvement of Highly Defective Quasi‐Mono Silicon Material by Phosphorus Diffusion Gettering

Liu

Vähänissi

Laine

et al. 2017

Adv Elect Materials

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Quasi‐mono silicon (QM‐Si) attracts interest as a substrate material for silicon device processing with the promise to yield single‐crystalline silicon quality with multicrystalline silicon cost. A significant barrier to widespread implementation of QM‐Si is ingot edge‐contamination caused by the seed material and crucible walls during crystal growth. This work aims to recover the scrap material in QM‐Si manufacturing with a process easily adaptable to semiconductor device manufacturing. A phosphorus diffusion process at 870 °C for 60 min significantly improves the electronic quality of a QM‐Si wafer cut from a contaminated edge brick. The harmonic minority carrier recombination lifetime of the wafer, a key predictor of ultimate device performance, experiences a tenfold increase from 17 to 178 µs, which makes the scrap QM‐Si material usable for device fabrication. Local areas with suboptimal (<50 µs) lifetimes remaining can be further improved by a high temperature anneal before the phosphorus diffusion process.

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Effect of ozone concentration on silicon surface passivation by atomic layer deposited Al2O3

Cited by 19 publications

References 28 publications

Ozone‐Based Atomic Layer Deposition of Al₂O₃ from Dimethylaluminum Chloride and Its Impact on Silicon Surface Passivation

Ozone‐Based Atomic Layer Deposition of Al₂O₃ from Dimethylaluminum Chloride and Its Impact on Silicon Surface Passivation

Recombination processes in passivated boron-implanted black silicon emitters

Electronic Quality Improvement of Highly Defective Quasi‐Mono Silicon Material by Phosphorus Diffusion Gettering

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Effect of ozone concentration on silicon surface passivation by atomic layer deposited Al2O3

Cited by 19 publications

References 28 publications

Ozone‐Based Atomic Layer Deposition of Al2O3 from Dimethylaluminum Chloride and Its Impact on Silicon Surface Passivation

Ozone‐Based Atomic Layer Deposition of Al2O3 from Dimethylaluminum Chloride and Its Impact on Silicon Surface Passivation

Recombination processes in passivated boron-implanted black silicon emitters

Electronic Quality Improvement of Highly Defective Quasi‐Mono Silicon Material by Phosphorus Diffusion Gettering

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Product

Resources

About

Ozone‐Based Atomic Layer Deposition of Al₂O₃ from Dimethylaluminum Chloride and Its Impact on Silicon Surface Passivation

Ozone‐Based Atomic Layer Deposition of Al₂O₃ from Dimethylaluminum Chloride and Its Impact on Silicon Surface Passivation