Ultrathin amorphous Si layer formation by femtosecond laser pulse irradiation

Izawa, Y.; Izawa, Yasukazu; Setsuhara, Yuichi; Hashida, Masaki; Fujita, Masayuki; Sasaki, Ryuichiro; Nagai, Hirokazu; Yoshida, Makoto

doi:10.1063/1.2431709

Cited by 75 publications

(49 citation statements)

References 14 publications

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“…Second, the thickness of the amorphous top layer is shallow and an increasing function of pulse number N. This accumulative behavior is quite similar to the well-known effect of a reduction of the ablation threshold for increasing pulse numbers, both being caused by an increase of the absorption coefficient and therefore an enhanced energy deposition during the first pulses. The thickness of laser-induced amorphous layers in Si has been investigated by Izawa et al using transmission electron microscopy performed at sample cross sections 8 . Using the same irradiation wavelength and pulse duration as ours, the authors reported a maximum thickness of 40 nm for N = 20 (the only N value they studied).…”

Section: Textmentioning

confidence: 99%

“…Lett. 110, 211602 (2017); doi: http://dx.doi.org/10.1063/1.4984110 2 laser pulse duration, wavelength and number of irradiation pulses, as well as film thickness and choice of substrate in the case of thin Si films [5][6][7][8][9][10] . Despite this early discovery, most laser-induced phase-change studies in Si focused on transforming large areas, for instance laser-annealing of amorphous Si for fabrication of solar cells 11,12 or OLED displays 13 .…”

Section: Textmentioning

confidence: 99%

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Fabrication of amorphous micro-ring arrays in crystalline silicon using ultrashort laser pulses

Fuentes‐Edfuf

García-Lechuga

Puerto

et al. 2017

Applied Physics Letters

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Abstract:We demonstrate a simple way to fabricate amorphous micro-rings in crystalline silicon using direct laser writing. The method is based on the fact that the phase of a thin surface layer can be changed into the amorphous phase by irradiation with a few ultrashort laser pulses (800 nm wavelength and 100 fs duration). Surface-depressed amorphous rings with a central crystalline disk can be fabricated without the need for beam shaping, featuring attractive optical, topographical, and electrical properties. The underlying formation mechanism and phase change path way have been investigated by means of fs-resolved microscopy, identifying fluence-dependent melting and solidification dynamics of the material as the responsible mechanism. We demonstrate that the lateral dimensions of the rings can be scaled and that the rings can be stitched together, forming extended arrays of structures not limited to annular shapes. This technique and the resulting structures may find applications in a variety of fields in optics, nanoelectronics, and mechatronics. Text:Silicon is more than just a key material for the electronics industry; it can be considered one of the pillars the industry is built on. Si owes this position essentially to its abundance on earth, its semiconducting properties and the existence of two structurally different solid phases (crystalline and amorphous), having very different physical properties. In this context it is worth noting that the amorphous phase can be formed by a variety of methods, including chemical and physical vapour deposition techniques, ion implantation and melting followed by rapid quenching. While some of the properties of the amorphous phase are known to depend on the preparation method 1 it has to be kept in mind that it is still a tetrahedrally coordinated semiconductor with a coordination number close to four 2 , just as the crystalline phase.Laser processing of Si started immediately after sufficiently intense lasers were available 3 and today applications are countless. The ability of pulsed laser irradiation to melt the crystalline material and induce resolidification either into the crystalline or amorphous phase, depending on the irradiation conditions, has been observed already in 1979 by Liu et al 4 . In fact, the authors proposed this concept for data storage applications due to the optical contrast between the two phases. Several experimental parameters influence the melting and freezing kinetics of the material and thus the final phase obtained, the most important ones being the Appl. Phys. Lett. 110, 211602 (2017); doi: http://dx.doi.org/10.1063/1.4984110 2 laser pulse duration, wavelength and number of irradiation pulses, as well as film thickness and choice of substrate in the case of thin Si films [5][6][7][8][9][10] . Despite this early discovery, most laser-induced phase-change studies in Si focused on transforming large areas, for instance laser-annealing of amorphous Si for fabrication of solar cells 11,12 or OLED displays 13 . Less work has been done to imp...

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Section: Textmentioning

confidence: 99%

Section: Textmentioning

confidence: 99%

Fabrication of amorphous micro-ring arrays in crystalline silicon using ultrashort laser pulses

Fuentes‐Edfuf

García-Lechuga

Puerto

et al. 2017

Applied Physics Letters

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“…It is apparent that the selective gold patterning over a large area was achieved. The processed area is expected to be amorphous silicon since it showed a higher reflectivity than that of the unprocessed area [2]. Both results from different processing tools indicated that gold precipitation with high density can be achieved when amorphous silicon phase was induced with a processing tool.…”

Section: Droppingmentioning

confidence: 68%

“…Furthermore, we showed that amorphous silicon induced by FIB-processing on the crystalline silicon surface played a crucial role in the growth of gold nanoparticles. Since amorphous silicon can also be induced using a pulsed laser [2], gold patterns can be achieved using a laser instead of an FIB.…”

Section: Introductionmentioning

confidence: 99%

Selective Growth and SERS Property of Gold Nanoparticles on Amorphized Silicon Surface

Matsuoka

Nishi

Sakakura

et al. 2011

IOP Conf. Ser.: Mater. Sci. Eng.

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“…It is known that the defects and amorphization of Si created by the preceding pulses at a prebreakdown threshold irradiance enhance the generation of free electrons and avalanche ionization [19]. Formation of amorphous silicon (a-Si) was reported for Si irradiated by fs-pulses: 0.18 J/cm 2 at 800 nm [20]. The thickness of a-Si was approximately 42 nm after six laser pulses with no changes in the a ∼ 2 nm thickness of native oxide observed [20].…”

Section: Nonlinear Optical Propertiesmentioning

confidence: 99%

Optical transmission and laser structuring of silicon membranes

Juodkazis¹,

Nishi²,

Misawa³

et al. 2009

Opt. Express

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Abstract:The optical linear and nonlinear properties of ∼ 340-nmthick Si membranes were investigated. The investigation included both experiments in which the reflection and transmission from the membranes were measured, and finite differences time domain simulations. The linear optical transmission of the Si membranes can be controlled by changing the thickness of a thermally grown oxide on the membrane. Illumination of the membranes with high levels of irradiation leads to optical modifications that are consistent with the formation of amorphous silicon and dielectric breakdown. When irradiated under conditions where dielectric breakdown occurs, the membranes can be ablated in a well-controlled manner. Laser micro-structuring of the membranes by ablation was carried out to make micrometer-sized holes by focused fs-pulses. Ns-pulses were also used to fabricate arrays of holes by proximity-ablation of a closely-packed pattern of colloidal particles.

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Ultrathin amorphous Si layer formation by femtosecond laser pulse irradiation

Cited by 75 publications

References 14 publications

Fabrication of amorphous micro-ring arrays in crystalline silicon using ultrashort laser pulses

Fabrication of amorphous micro-ring arrays in crystalline silicon using ultrashort laser pulses

Selective Growth and SERS Property of Gold Nanoparticles on Amorphized Silicon Surface

Optical transmission and laser structuring of silicon membranes

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