Etching methods for texturing industrial multi-crystalline silicon wafers: A comprehensive review

ABSTRACTWe propose an implementation of the PCD technique to minority carrier effective lifetime assessment in crystalline silicon at 77K. We focus here on (n)-type, FZ, polished wafers passivated by a-Si:H deposited by PECVD at 200°C. The samples were immersed into liquid N2 contained in a beaker placed on a Sinton lifetime tester. Prior to be converted into lifetimes, data were corrected for the height shift induced by the beaker. One issue lied in obtaining the sum of carrier mobilities at 77K. From dark conductance measurements performed on the lifetime tester, we extracted an electron mobility of 1.1x104 cm².V-1.s-1 at 77K, the doping density being independently calculated in order to account for the freezing effect of dopants. This way, we could obtain lifetime curves with respect to the carrier density. Effective lifetimes obtained at 77K proved to be significantly lower than at RT and not to depend upon the doping of the a-Si:H layers. We were also able to experimentally verify the expected rise in the implied Voc, which, on symmetrically passivated wafers, went up from 0.72V at RT to 1.04V at 77K under 1 sun equivalent illumination.

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Micro Electrical Discharge Machining Thermal Effect on Micro-Cracks Generation on Silicon Material

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1047.41 ◽

2021 ◽

Vol 1047 ◽

pp. 41-49

Author(s):

Xiao Zhong Song

Keyword(s):

Electrical Discharge Machining ◽

Crystalline Silicon ◽

Local Area ◽

Silicon Wafers ◽

Adverse Side Effect ◽

Micro Edm ◽

Crystalline Orientation ◽

Surface Machining ◽

Crack Generation ◽

Micro Cracks

Various novel 3D micro machining technologies were researched and developed for silicon micro mechanical system fabrication. Micro EDM is one of them. The material removal mechanism is thermal sparking erosion and is completely independent with regards to the crystalline orientation of silicon, therefore there is no orientation constraint in processing the complex 3D geometry of silicon wafers. As thermal sparking implied, the process features local area high temperature melting and evaporating, and this characteristic has an adverse side-effect on the sparked surface integrity. One important concern is the generation of micro cracks, which would provide an adverse effect on the fatigue life of the micro feature element made of silicon. For this consideration, in this paper, with the experiment and SEM picture analysis approach, the author explored the micro crack generation characteristics on mono crystalline silicon wafers under micro EDM with available sparking energies and on the different crystal orientation surface machining. The generation of micro cracking is not only related with the sparking energy but also related with the crystalline orientation. The {100} orientation is the strongest surface to resist crack generation. For a strong-doped P type silicon wafer, there exists a maximum crack energy threshold. If single sparking energy is over this threshold, micro cracks unavoidably would be generated on any orientation surface. Two types of chemical etching post processes that can remove cracks on sparked surfaces are also tested and discussed.

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Thermal pretreatment of diamond wire sawn multi-crystalline silicon wafers for wet acid texturization of solar cells

Materials Research Express ◽

10.1088/2053-1591/aaf118 ◽

2018 ◽

Vol 6 (2) ◽

pp. 025911

Author(s):

Jinbing Zhang ◽

Hongping Fu ◽

Xingfang Ye ◽

Lang Zhou

Keyword(s):

Solar Cells ◽

Crystalline Silicon ◽

Silicon Wafers ◽

Thermal Pretreatment ◽

Diamond Wire

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B35 Study on laser recovery of wire saw-damaged poly-crystalline silicon wafers

The Proceedings of The Manufacturing & Machine Tool Conference ◽

10.1299/jsmemmt.2014.10.119 ◽

2014 ◽

Vol 2014.10 (0) ◽

pp. 119-120

Author(s):

Keiichiro NIITSU ◽

Jiwang YAN

Keyword(s):

Crystalline Silicon ◽

Silicon Wafers ◽

Wire Saw

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Complete Recovery of Subsurface Structures of Machining-Damaged Single Crystalline Silicon by Nd:YAG Laser Irradiation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.389-390.469 ◽

2008 ◽

Vol 389-390 ◽

pp. 469-474 ◽

Cited By ~ 2

Author(s):

Ji Wang Yan ◽

Tooru Asami ◽

Tsunemoto Kuriyagawa

Keyword(s):

Nd:Yag Laser ◽

Crystalline Silicon ◽

Laser Energy ◽

Recovery Process ◽

Complete Recovery ◽

Amorphous Layer ◽

Boundary Region ◽

Silicon Wafers ◽

Near Surface ◽

Transmission Electron

Ultraprecision diamond-cut silicon wafers were irradiated by a nanosecond pulsed Nd:YAG laser, and the resulting specimens were characterized using transmission electron microscopy and micro-Raman spectroscopy. The results indicate that at specific laser energy density levels, machining-induced amorphous layers and dislocated layers were both reconstructed to a complete single-crystal structure identical to the bulk region. Similar effects were confirmed for diamond-ground silicon wafers. Effects of overlapping irradiation were investigated and perfect crystallographic uniformity was achieved in the boundary region. The recovery process involved rapid melting of the near-surface amorphous layer, followed by epitaxial regrowth from the damage-free crystalline bulk.

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Hydrogen and Deuterium in Semi-Crystalline Silicon Wafers and Solar Cells

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.37-38.355 ◽

1994 ◽

Vol 37-38 ◽

pp. 355-360 ◽

Cited By ~ 1

Author(s):

A.W. Weeber ◽

H.H.C. de Moor ◽

R.A. Steeman ◽

W.C. Sinke ◽

F. Schuurmans ◽

...

Keyword(s):

Solar Cells ◽

Crystalline Silicon ◽

Silicon Wafers

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Optical Properties of Spin-Coated TiO2Antireflection Films on Textured Single-Crystalline Silicon Substrates

International Journal of Photoenergy ◽

10.1155/2015/147836 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 6

Author(s):

Ryosuke Watanabe ◽

Yohei Eguchi ◽

Takuya Yamada ◽

Yoji Saito

Keyword(s):

Optical Properties ◽

Crystalline Silicon ◽

Low Cost ◽

Incident Light ◽

Antireflection Coating ◽

Silicon Wafers ◽

Reflectance Spectra ◽

Visible Range ◽

Single Crystalline Silicon ◽

Single Crystalline

Antireflection coating (ARC) prepared by a wet process is beneficial for low cost fabrication of photovoltaic cells. In this study, we investigated optical properties and morphologies of spin-coated TiO2ARCs on alkaline textured single-crystalline silicon wafers. Reflectance spectra of the spin-coated ARCs on alkaline textured silicon wafers exhibit no interferences and low reflectance values in the entire visible range. We modeled the structures of the spin-coated films for ray tracing numerical calculation and compared numerically calculated reflectance spectra with the experimental results. This is the first report to clarify the novel optical properties experimentally and theoretically. Optical properties of the spin-coated ARCs without interference are due to the fractional nonuniformity of the thickness of the spin-coated ARCs that cancels out the interference of the incident light.

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