Characteristics of Hydrogen Effusion from the Si-H Bonds in Si Rich Silicon Oxynitride Films for Nanocrystalline Silicon Based Photovoltaic Applications

2013 ◽  
Vol 854 ◽  
pp. 69-74 ◽  
Author(s):  
Andrey Sarikov ◽  
M. Voitovych ◽  
Igor Lisovskyy ◽  
V. Naseka ◽  
A. Hartel ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Silicon Oxynitride ◽  
Tandem Solar Cells ◽  
Si Nanocrystals ◽  
Photovoltaic Applications ◽  
Silicon Based ◽  
Kinetics Of ◽  
Hydrogen Effusion

This work is devoted to determination of characteristics of hydrogen effusion from SiH bonds in Si rich silicon oxynitride (SRON) films, obtained by plasma enhanced chemical vapor deposition, as a result of thermal anneals at temperatures from 400 to 800°C. The values of the concentrations of SiH bonds in HSi (Si3nOn) (0 n 3) complexes contributing to the structure of SRON films are obtained from the analysis of infrared absorption spectra in the range of 2000-2400 cm1. The kinetics of the decrease of SiH concentrations as a result of anneals is described in the framework of a model with distributed activation energy of hydrogen emission. The median value and the mean-square deviation of this distribution as well as the attempt frequencies of SiH bond breaks are determined from the comparison of experimental and calculated SiH concentrations in SRON films. These characteristics are compatible with such characteristics found for the case of the depassivation of PbH centers at the Si/SiO2 interfaces. Obtained results are useful for the controlled formation of the layers of Si nanocrystals in dielectric matrix for Si based tandem solar cells applications.

Effect of C and Ge Concentration On The Thermal Stability of RTCVD Grown Si1-x-yGexCy Alloys

1997 ◽  
Vol 470 ◽  
Author(s):  
Patricia Warren ◽  
Stephane Retzmanick ◽  
Martin Gotza ◽  
Marc Begems
Keyword(s):  
Lattice Constant ◽  
Strain Relaxation ◽  
Mechanical Strain ◽  
Chemical Vapor ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
Cubic Silicon Carbide ◽  
Kinetics Of ◽  
Good Agreement

ABSTRACTSi / Si1-x-yGexCy / Si heterostructures containing up to 17 at.% Ge and 1.9 at.% C were grown on (001) silicon by low pressure Rapid Thermal Chemical Vapor Deposition, using a mixture of silane, germane and methylsilane, diluted in hydrogen. The samples were then annealed in a Rapid Thermal Processing furnace, under an atmospheric pressure of nitrogen, at temperatures ranging from 900 to 1130 °C.The samples were characterized using infrared spectroscopy and x-ray diffraction. SIMS profiling and TEM observation were performed on some of the samples.Substitutional C gradually disappeared, either precipitating out to form cubic silicon carbide (β-SiC), or simply vanishing into interstitial positions. In any case, the in-plane lattice constant remained constant after annealing, indicating that there was no mechanical strain relaxation by formation of misfit dislocations. The perpendicular lattice constant increased due to the decrease in substitutional C concentration, as well as it decreased due to the germanium out-diffusion. This variation of the strain during annealing was modeled, and allowed the determination of the kinetics of the substitutional carbon disappearance. The same behavior was observed for all samples. Indeed, the Cs disappearance rate was always increased for samples with higher initial Ge and C concentrations. The kinetics of this precipitation was found in very good agreement with previous published results.

A Low Temperature Photonic Crystal Technology for Integration with Modern CMOS Technologies

2007 ◽  
Vol 990 ◽  
Author(s):  
Khadijeh Bayat ◽  
Mahdi Farrokh Baroughi ◽  
Sujeet K. Chaudhuri ◽  
Safieddin Safavi-Naeini
Keyword(s):  
Photonic Crystal ◽  
Low Temperature ◽  
Integrated Circuits ◽  
Gas Phase ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Silicon Oxynitride ◽  
Refractive Indices ◽  
Optical Integrated Circuits ◽  
Silicon Based

ABSTRACTIn this paper, low temperature amorphous silicon oxynitride (a-SixOyNz:H) thin film technology is proposed for implementation of CMOS compatible photonic crystal (PC) based optical integrated circuits (OICs). The a-SixOyNz films of different refractive indices were developed by plasma enhanced chemical vapor deposition (PECVD) technique using silane, nitrous oxide, and ammonia as gas phase precursors at 300°C. The films with refractive index between 1.43 − 1.75 were obtained by changing gas flow ratios. Such thin films can be used as cladding and core layers in photonic crystal structure.The bandgap and guiding properties of the a-SixOyNz based PCs were simulated and was shown that the a-SixOyNz:H based PC technology offers larger feature sizes than a conventional silicon based photonic crystals.

Hydrogen Passivation Kinetics of Si Nanocrystals in SiO2

2003 ◽  
Vol 770 ◽  
Author(s):  
Andrew R. Wilkinson ◽  
Robert G. Elliman
Keyword(s):  
Reaction Kinetics ◽  
Activation Energies ◽  
Hydrogen Passivation ◽  
Time Resolved ◽  
Luminescence Efficiency ◽  
Si Nanocrystals ◽  
Preliminary Study ◽  
Kinetics Of ◽  
Insight Into

AbstractHydrogen passivation of non-radiative defects increases the luminescence intensity from silicon nanocrystals. In this study, photoluminescence (PL) and time-resolved PL were used to investigate the chemical kinetics of the hydrogen passivation process. Isochronal and isothermal annealing sequences were used to determine the reaction kinetics for the absorption and desorption of hydrogen, using the generalised consistent simple thermal (GST) model proposed by Stesmans for Pb defects at planar Si/SiO2 interfaces. This included determination of the activation energies and rate constants for the forward and reverse reactions as well as the associated spread in activation energies. The reaction kinetics determined from such measurements were found to be in excellent agreement with those for the passivation of Pb defects at planar Si/SiO2 interfaces, suggesting the nanocrystal emission process is also limited by such defects. These results provide useful model data as well as insight into the processing conditions needed to achieve optimum passivation in H2. As an extension to the work, a preliminary study into passivation by atomic hydrogen was pursued via a post-metallization Al anneal (alneal). A considerable gain in luminescence efficiency was achieved over the previously optimised passivation in H2.

Nucleation and growth of Si quantum nanocrystals in silicon-rich oxide films

1996 ◽  
Vol 54 ◽  
pp. 234-235
Author(s):  
S. C. Mehta ◽  
D. A. Smith ◽  
M. R. Libera ◽  
J. Ott ◽  
G. Tompa ◽  
...  
Keyword(s):  
Amorphous Matrix ◽  
Bulk Diffusion ◽  
Nucleation And Growth ◽  
Light Emitters ◽  
Si Nanocrystals ◽  
Uniform Dispersion ◽  
Silicon Nanocrystallites ◽  
Image Position ◽  
Silicon Based ◽  
Kinetics Of

The observation of photoluminescence and electroluminescence in Si nanocrystals has generated renewed interest in these novel silicon based materials for their possible application as light emitters and detectors. Silicon Rich Oxide (SRO) films with a uniform dispersion of silicon nanocrystallites in a wider bandgap SiO2 matrix manifest electroluminescence and photoluminescence in the infrared and visible portions of the spectrum. Understanding the nucleation and growth kinetics of these crystallites in amorphous matrix is of critical importance in the fabrication of future optoelectronic devices. One route to the fabrication of Si nanocrystals is by the crystallization of amorphous SiO2-x. Consider the case when x=1. The reaction leading to the formation of Si crystallites can be written as;(1)The nucleation, growth and coarsening processes of Si nanocrystals each require bulk diffusion of Si atoms through the amorphous matrix.

Preparation and Characterization of Silicon Nanocrystals in a SiO2 Matrix and Study of Suboxide Stability

1996 ◽  
Vol 452 ◽  
Author(s):  
B. J. Hinds ◽  
A. Banerjee ◽  
R. S. Johnson ◽  
G. Lucovsky
Keyword(s):  
Chemical Vapor ◽  
Decomposition Reaction ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Si Nanocrystals ◽  
Metastable Form ◽  
C 30 ◽  
Kinetics Of ◽  
Post Deposition

AbstractThe kinetics of the decomposition of silicon suboxides (SiOx, x<2) to Sic + SiO2 was studied as a function of composition and post-deposition annealing. Amorphous hydrogenated SiOx films (0.8<x<1.4) were deposited by remote plasma enhanced chemical vapor deposition (RPECVD) and rapid thermal annealed (RTA) at temperatures of 500–1000°C. By monitoring the Si-O infra-red (IR) bond-stretch mode frequency, it was found that at temperatures below 850°C, or at a oxygen poor composition near SiO0.8, the decomposition reaction only proceeded to a metastable form of SiO1.6 + Si. Characterization by Raman and spectroscopie ellipsometry confirm similar trends. Cross sectional transmission electron microscopy (TEM) confirms that Si nanocrystals (Sine) are formed with anneals at 900°C (30 sec). As deposited suboxides show band edge photoluminescence at 1.6 eV which disappears upon annealing at 900°C, indicating a sharp suboxide free interface between Sinc and SiO2 matrix.

Protocrystalline Growth of Silicon below 80°C

2000 ◽  
Vol 609 ◽  
Author(s):  
Christian Koch ◽  
Manabu Ito ◽  
Vlado Svrcek ◽  
Markus B. Schubert ◽  
Jürgen H. Werner
Keyword(s):  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Absolute Constant ◽  
Fill Factor ◽  
Chemical Vapor ◽  
Optical Characterization ◽  
Nanocrystalline Silicon ◽  
Crucial Importance ◽  
Silicon Based ◽  
Nanocrystalline Phases

ABSTRACTProtocrystalline silicon deposited at temperatures below 80°C exhibits an extraordinary photosensitivity and superior stability against light-soaking. This material growths at the borderline of the amorphous and nanocrystalline phases in plasma-enhanced chemical vapor deposition. After thermal annealing and subsequent light-soaking, the photosensitivity is comparable to the values after deposition, while amorphous silicon strongly drops off. A structural and optical characterization reveals a small fraction of silicon crystallites embedded in an amorphous well-ordered matrix. We investigate the morphology of silicon films deposited at the edge of crystallinity by the absolute Constant Photocurrent Method and observe a phase transition from amorphous to nanocrystalline silicon. This thickness dependant morphology is of crucial importance for solar cell design. We attain protocrystalline absorber which reflect in a strongly improved fill factor compared to amorphous silicon based solar cells.

Ion Beam Induced Interfacial Reactions in Molybdenum Thin Films on Silicon

1981 ◽  
Vol 39 ◽  
pp. 162-163
Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Ion Beam ◽  
Chemical Vapor ◽  
Interfacial Reactions ◽  
Practical Applications ◽  
Microelectronic Devices ◽  
Recent Emergence ◽  
Chemical Vapor Deposited ◽  
Atomic Mixing ◽  
Silicon Interface ◽  
Kinetics Of

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.

In situ study of electron beam-induced chemical vapor deposition of Au in an environmental TEM

1995 ◽  
Vol 53 ◽  
pp. 256-257
Author(s):  
J. Drucker ◽  
R. Sharma ◽  
J. Kouvetakis ◽  
K.H.J. Weiss
Keyword(s):  
Electron Beam ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Quantum Effect ◽  
Line Drawing ◽  
Chemical Vapor ◽  
Environmental Cell ◽  
Engineering Changes ◽  
Kinetics Of

Patterning of metals is a key element in the fabrication of integrated microelectronics. For circuit repair and engineering changes constructive lithography, writing techniques, based on electron, ion or photon beam-induced decomposition of precursor molecule and its deposition on top of a structure have gained wide acceptance Recently, scanning probe techniques have been used for line drawing and wire growth of W on a silicon substrate for quantum effect devices. The kinetics of electron beam induced W deposition from WF6 gas has been studied by adsorbing the gas on SiO2 surface and measuring the growth in a TEM for various exposure times. Our environmental cell allows us to control not only electron exposure time but also the gas pressure flow and the temperature. We have studied the growth kinetics of Au Chemical vapor deposition (CVD), in situ, at different temperatures with/without the electron beam on highly clean Si surfaces in an environmental cell fitted inside a TEM column.

Determination of creep mechanisms in various silicon carbides via TEM

1986 ◽  
Vol 44 ◽  
pp. 484-487
Author(s):  
C. H. Carter ◽  
J. E. Lane ◽  
J. Bentley ◽  
R. F. Davis
Keyword(s):  
Heat Exchangers ◽  
Sintered Material ◽  
Polycrystalline Material ◽  
Chemical Vapor ◽  
Graphite Substrate ◽  
Second Phase ◽  
Reaction Bonding ◽  
Creep Mechanisms ◽  
Porous Sic

Silicon carbide (SiC) is the generic name for a material which is produced and fabricated by a number of processing routes. One of the three SiC materials investigated at NCSU is Norton Company's NC-430, which is produced by reaction-bonding of Si vapor with a porous SiC host which also contains free C. The Si combines with the free C to form additional SiC and a second phase of free Si. Chemical vapor deposition (CVD) of CH3SiCI3 onto a graphite substrate was employed to produce the second SiC investigated. This process yielded a theoretically dense polycrystalline material with highly oriented grains. The third SiC was a pressureless sintered material (SOHIO Hexoloy) which contains B and excess C as sintering additives. These materials are candidates for applications such as components for gas turbine, adiabatic diesel and sterling engines, recouperators and heat exchangers.

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