Understanding the thickness-dependent effective lifetime of crystalline silicon passivated with a thin layer of intrinsic hydrogenated amorphous silicon using a nanometer-accurate wet-etching method

2016 ◽  
Vol 119 (23) ◽  
pp. 235307 ◽  
Author(s):  
Dimitrios Deligiannis ◽  
Vasileios Marioleas ◽  
Ravi Vasudevan ◽  
Cassan C. G. Visser ◽  
René A. C. M. M. van Swaaij ◽  
...  
Keyword(s):  
Thin Layer ◽  
Amorphous Silicon ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Wet Etching ◽  
Effective Lifetime ◽  
Etching Method ◽  
Hydrogenated Amorphous

Crystalline Silicon Surface Passivation by Pecv-Deposited Hydrogenated Amorphous Silicon Oxide Films [a-SiOx:H]

2007 ◽  
Vol 989 ◽  
Author(s):  
Thomas Mueller ◽  
Wolfgang Duengen ◽  
Reinhart Job ◽  
Maximilian Scherff ◽  
Wolfgang Fahrner
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Thermal Annealing ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Window Layer ◽  
Effective Lifetime ◽  
Si Solar Cells ◽  
Hydrogenated Amorphous

AbstractIn the research field of crystalline silicon (c-Si) solar cells, electronic surface passivation has been recognized as a crucial step to achieve high conversion efficiencies. The main issue of this article is to analyze the surface passivation properties of both, n-type and p-type crystalline silicon wafers by hydrogenated amorphous silicon sub oxide [a-SiOx:H] films the for use in hetero-junction (a-Si/c-Si) solar cells. A window layer is obtained with a certain fraction of oxygen in the a-SiOx:H layers.The a-SiOx:H films were deposited by decomposition of silane, carbon dioxide and hydrogen as source gases using plasma enhanced chemical vapor deposition (PECVD). Films with varying deposition parameters such as gas flow ratio (oxygen fraction) and plasma frequency (13.56, 70.0 and 110.0 MHz) are compared.To determine the passivation quality of the a-SiOx:H films, microwave-detected photo conductance decay (µ-PCD) provides a contactless measurement of the effective recombination lifetime of free carriers. The film compositions and also the changes in the microscopic structure of the amorphous network upon thermal annealing are studied using Raman spectroscopy and optical profiling techniques.The Raman spectra reveal the generation of Si-(OH)x and Si-O-Si bonds after thermal annealing in the layers, leading to a higher effective lifetime, as it reduces the defect absorption of the sub oxides.For n-type FZ material, lifetime values as high as 1650 µs are obtained, resulting in a surface recombination velocity Seff < 9.5 cm/s.

scholarly journals High quality crystalline silicon surface passivation by combined intrinsic and n-type hydrogenated amorphous silicon

2011 ◽  
Vol 99 (20) ◽  
pp. 203503 ◽  
Author(s):  
Jan-Willem A. Schüttauf ◽  
Karine H. M. van der Werf ◽  
Inge M. Kielen ◽  
Wilfried G. J. H. M. van Sark ◽  
Jatindra K. Rath ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Silicon Surface ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
High Quality ◽  
Hydrogenated Amorphous ◽  
Silicon Surface Passivation

Hall-Effect and Sign Properties in Hydrogenated Amorphous and Disordered Crystalline Silicon

1996 ◽  
Vol 420 ◽  
Author(s):  
C. E. Nebel ◽  
M. Rother ◽  
C. Summonte ◽  
M. Heintze ◽  
M. Stutzmann
Keyword(s):  
Hall Effect ◽  
Amorphous Silicon ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Small Volume Fraction ◽  
Phosphorus Doped ◽  
Hydrogenated Amorphous ◽  
Defect Densities ◽  
Very High

AbstractHall experiments on a series of microcrystalline, microcrystalline-amorphous, amorphous and crystalline silicon samples with varying defect densities are presented and discussed. Normal Hall effect signatures on boron and phosphorus doped hydrogenated amorphous silicon are detected. We interpret these results to be due to a small volume fraction of nanocrystalline Si, which falls below the detection limits of Raman experiments. Hydrogenated amorphous silicon, prepared under conditions far away from microcrystalline growth, shows the known double sign anomaly, Sign reversals in c-Si, where the disorder is increased by Si implantation up to very high levels, could not be detected.

Modulation of Growing Surface with Atomic Hydrogen and Excited Argon to Fabricate Narrow Gap a-Si:H

1996 ◽  
Vol 420 ◽  
Author(s):  
W. Futako ◽  
I. Shimizu ◽  
C. M. Fortmann
Keyword(s):  
Thin Layer ◽  
Substrate Temperature ◽  
Amorphous Silicon ◽  
Atomic Hydrogen ◽  
Hydrogenated Amorphous Silicon ◽  
High Substrate Temperature ◽  
Narrow Gap ◽  
High Quality ◽  
Chemical Annealing ◽  
Hydrogenated Amorphous

AbstractHydrogenated amorphous silicon (a-Si:H) with a gaps narrower than 1.7 eV were made by repeating the deposition of a thin layer (1–3 nm thick) and the treatment of growing surface with a mixture of H and Ar*. Crystallization induced by permeation of hydrogen into the subsurface at high substrate temperature (>200C) was efficiently prevented by treating with a mixture of H and Ar*. The activation of growing surface may arise from releasing a part of hydrogen on surface by treating with Ar*. High quality a-Si:H films containing hydrogen of 3 atom % with a gap of 1.6 eV were made by chemical annealing with a mixture of H and Ar*.

scholarly journals Anisotropy in Hydrogenated Amorphous Silicon Films as Observed Using Polarized Ftir-Atr Spectroscopy

1999 ◽  
Vol 557 ◽  
Author(s):  
J. D. Webb ◽  
L. M. Gedvilas ◽  
R. S. Crandall ◽  
E. Iwaniczko ◽  
B. P. Nelson ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Film Growth ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Impurity Band ◽  
Attenuated Total Reflection ◽  
Structural Anisotropy ◽  
Si Films ◽  
Polarized Ftir ◽  
Hydrogenated Amorphous

AbstractWe used polarized attenuated total reflection (ATR) measurements together with Fourier transform infrared (FTIR) spectroscopy to investigate the vibrational spectra of hydrogenated amorphous silicon (a-SiHx) films 0.5-1.0 microns in thickness. We deposited the films using hot-wire or plasma-enhanced chemical vapor deposition methods (HWCVD or PECVD, respectively) on crystalline silicon and cadmium telluride substrates. Our ATR technique gave a spectral range from 2100-400 cm-1, although the Si-H wagging mode absorption band at 640 cm-1 was somewhat distorted in the a-SiHx/Si samples by impurity and lattice absorption in the silicon ATR substrates. We report the identification of a Si-O-C impurity band with maximum intensity at 1240-1230 cm-1. The assignment of this band to a Si-O-C vibration is supported by secondary-ion mass spectrometry (SIMS) measurements. Our polarized FTIR-ATR spectra of HWCVD and PECVD a-SiHx films on <111> Si ATR substrates show that the impurity dipoles are oriented strongly parallel to the film growth direction. The wagging mode absorbance band is more intense in the film plane. This trend is less pronounced for the Si-H stretching vibrations. These observations are consistent with some degree of anisotropy or medium-range order in the films. The anisotropy in the Si-H bands may be related to residual stress in the films. Our scanning electron microscopy (SEM) analyses of the samples offer additional evidence of bulk structural anisotropy in the a-SiHx/Si films. However, the Si-O-C impurity band was not observed in the polarized ATR-FTIR spectra of the a-SiHx/CdTe samples, thus indicating that the Si substrates influence formation of the impurity in the a-SiHx/Si films.

Photo-Oxidation of Hydrogenated Amorphous Silicon-Carbon Alloys

1989 ◽  
Vol 158 ◽  
Author(s):  
P. John ◽  
I.M. Odeh ◽  
A. Qayyum ◽  
J.I.B. Wilson
Keyword(s):  
Amorphous Silicon ◽  
Photoelectron Spectroscopy ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Rf Discharge ◽  
Silicon Substrates ◽  
Capacitively Coupled ◽  
X Ray ◽  
Silicon Carbon ◽  
Hydrogenated Amorphous

ABSTRACTHydrogenated amorphous silicon-carbon alloys, a-Si:C:H, have been deposited as thin films (d=0.1-0.5 micron) on crystalline silicon substrates from a capacitively coupled rf discharge in silane-propane mixtures. Variations in the stoichiometry of the films were achieved by altering the ratio of SiH4 to C3H8 flow rates at a sbstrate temperature in the range 240-260°C and total pressure between 30-70 mtorr. The silicon to carbon ratios were established by X-ray photoelectron spectroscopy, XPS, and the hydrogen content and distribution by infra-red spectroscopy.

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