Ftir and UV Study of Amorphous Silicon-Boron Alloys Deposited by LPCVD

1996 ◽  
Vol 426 ◽  
Author(s):  
G.-R. Yang ◽  
Y.-P. Zhao ◽  
B. Y. Tong
Keyword(s):  
Boron Content ◽  
Optical Band Gap ◽  
Uv Spectroscopy ◽  
Oxidation Mechanism ◽  
Chemical Vapor ◽  
Structure Change ◽  
Narrow Gap ◽  
Photovoltaic Devices ◽  
Pressure Chemical ◽  
Oxidation Behaviors

AbstractAs-deposited and wet oxidized a-Si:B alloy deposited by low pressure chemical vapor deposition (LPCVD) with various boron content was studied by UV Spectroscopy and Fourier Transform Infrared Spectroscopy. It is found that the optical band gap of a-Si:B varies with respect to the boron content, which provides potential application probability in narrow-gap photovoltaic devices. This effect is associated with the structure change induced by B content. The oxidation behaviors of a-Si:B films with boron content 3 at.% – 25 at.% are different from those with boron content exceeded 30 at.%. Possible oxidation mechanism for different boron content a-Si:B film are proposed.

Variation de la contrainte des verres de silice sous cycle thermique

1992 ◽  
Vol 70 (10-11) ◽  
pp. 830-833
Author(s):  
H. Bouchard ◽  
A. Azelmad ◽  
J. F. Currie ◽  
M. Meunier
Keyword(s):  
Initial Stress ◽  
Vapor Deposition ◽  
Boron Content ◽  
Annealing Temperature ◽  
Chemical Vapor ◽  
Boron Doping ◽  
Pressure Chemical ◽  
Phosphosilicate Glass ◽  
Borophosphosilicate Glass

Using an in situ technique, stress was measured as a function of annealing temperature to investigate the effect of phosphorous and boron doping of silicon dioxide glass films deposited by low-pressure chemical vapor deposition (LPCVD). It was found that the initial stress of phosphosilicate glass is independent of the amount of phosphorus present, while the boron content influences the initial stress in borophosphosilicate glass. The stress increases to a maximum, σm, corresponding to a temperature Tm, above which the onset of viscous flow reduces the stress to zero at a temperature T0. All these parameters are dependant on dopant concentrations. The observed mechanical behavior is discussed in terms of film viscosity.

scholarly journals Accessing new 2D semiconductors with optical band gap: synthesis of iron-intercalated titanium diselenide thin films via LPCVD

RSC Advances ◽  
2018 ◽  
Vol 8 (40) ◽  
pp. 22552-22558 ◽  
Author(s):  
Clara Sanchez-Perez ◽  
Caroline E. Knapp ◽  
Ross H. Colman ◽  
Carlos Sotelo-Vazquez ◽  
Raija Oilunkaniemi ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Band Gap ◽  
Vapor Deposition ◽  
Optical Band Gap ◽  
Chemical Vapor ◽  
Single Source ◽  
2D Semiconductors ◽  
Single Source Precursor ◽  
Pressure Chemical

Fe-doped TiSe2 thin-films were synthesized via low pressure chemical vapor deposition (LPCVD) of a single source precursor: [Fe(η5-C5H4Se)2Ti(η5-C5H5)2]2 (1).

Study of Oxidation Properties of Amorphous Si:B Films

1991 ◽  
Vol 219 ◽  
Author(s):  
G.-R. Yang ◽  
T. C. Nason ◽  
Y.-J. Wu ◽  
B. Y. Tong ◽  
S. K. Wong
Keyword(s):  
Thermal Oxidation ◽  
Boron Content ◽  
Boron Concentration ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Vapor ◽  
Spectroscopic Properties ◽  
Threshold Temperature ◽  
Oxide Layers ◽  
Pressure Chemical ◽  
Secondary Ion

ABSTRACTThin films of an amorphous silicon-boron alloy with boron content 1–50 at.% have been deposited by low pressure chemical vapor deposition (LPCVD). The boron content and film thickness of the samples were controlled by regulating the ratio of diborane and silane gases during the deposition. It was observed that the crystallization of the amorphous alloy took place at higher temperatures as boron concentration was increased. After a thermal oxidation was performed, the stoichiometry of die resulting oxide layers on various samples was determined by the secondary ion mass spectrometry and Auger depth profile methods. While the threshold temperature for thermal oxidation was determined to be inversely proportional to the boron concentration, the oxidation rate showed a dramatic increase with boron content. In particular, an alloy containing 30% boron was readily oxidized at 500°C. Mechanisms for the enhancement of oxidation consistent with stoichiometric and spectroscopic properties of the oxide layers are discussed.

Raman Studies of Microstructural Changes in Amorphous Silicon-Boron Alloys Due to Annealing

1989 ◽  
Vol 164 ◽  
Author(s):  
G. Yang ◽  
P. Bai ◽  
Y.-J Wu ◽  
B. Y. Tong ◽  
S. K. Wong ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Boron Content ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Alloy Films ◽  
Si Substrates ◽  
Pressure Chemical ◽  
Crystalline Component

AbstractCrystallization of amorphous Sil−x.Bx alloy films by annealing is studied. Amorphous Sil−xBx. alloy films with composition of boron x ranging from 0.01 to 0.5 are deposited on Si substrates at a temperature of 480° in a low pressure chemical vapor deposition (LPCVD) system. Three films with the boron contents, 1%, 7% and 45%, are used in this study. The films are annealed in a nitrogen ambient for 30 minutes at temperatures between 600°C and 900°C. Raman spectra of the silicon vibrational mode serve as a indicator for the microstructure of the Sil−xBx, alloy films. Quantitative estimates of the volume fraction of the crystalline silicon component in respect to the amorphous silicon component in the films are calculated based on the silicon TO mode. The results show that while for the film with the boron content of 1% crystallization occurs at the annealing temperature of 500°C, the annealing temperature of 7000C is required to observe crystallization in the films with the boron contents of 7% and 45%. As the annealing temperature increases, the volume fraction of the crystalline component increases. For a given annealing temperature, the rate of crystallization depends inversely on the boron content in the films.

Growth of hematite on (0001) and {1102} sapphire substrates

1990 ◽  
Vol 48 (4) ◽  
pp. 376-377
Author(s):  
Lisa A. Tietz ◽  
Scott R. Summerfelt ◽  
C. Barry Carter
Keyword(s):  
Imaging Techniques ◽  
Chemical Vapor ◽  
Interface Energy ◽  
Dark Field ◽  
Cation Sublattice ◽  
Sapphire Substrates ◽  
Dark Field Imaging ◽  
Weak Beam ◽  
Pressure Chemical ◽  
Interface Structures

Defects in thin films are often introduced at the substrate-film interface during the early stages of growth. The interface structures of semiconductor heterojunctions have been extensively studied because of the electrical activity of defects in these materials. Much less attention has been paid to the structure of oxide-oxide heterojunctions. In this study, the structures of the interfaces formed between hematite (α-Fe2O3) and two orientations of sapphire (α-Al2O3) are examined in relationship to the defects introduced into the hematite film. In such heterojunctions, the oxygen sublattice is expected to have a strong influence on the epitaxy; however, defects which involve only the cation sublattice may be introduced at the interface with little increase in interface energy.Oxide heterojunctions were produced by depositing small quantities of hematite directly onto electrontransparent sapphire substrates using low-pressure chemical vapor deposition. Prior to deposition, the ionthinned substrates were chemically cleaned and annealed at 1400°C to give “clean”, crystalline surfaces. Hematite was formed by the reaction of FeCl3 vapor with water vapor at 1150°C and 1-2 Torr. The growth of the hematite and the interface structures formed on (0001) and {102} substrates have been studied by bright-field, strong- and weak-beam dark-field imaging techniques.

Light-Induced Degradation in Solar Cells with Hydrogenated Amorphous Silicon-Sulfur Active Layers

2002 ◽  
Vol 715 ◽  
Author(s):  
Wei Xu ◽  
P. C. Taylor
Keyword(s):  
Solar Cells ◽  
Practical Importance ◽  
Chemical Vapor ◽  
Photovoltaic Devices ◽  
Sulfur Concentration ◽  
Active Layers ◽  
Conversion Efficiencies ◽  
Hydrogenated Amorphous ◽  
Secondary Ion ◽  
Initial Conversion

AbstractWe have made a series of a-SiSx:H based solar cells, with a pin structure, in a multichamber plasma enhanced chemical vapor deposition (PECVD) system. The sulfur concentration ranges from zero to 5 x 1018 cm-3 as measured by secondary ion mass spectroscopy. The initial conversion efficiencies of cells in this series with sulfur concentrations ≤ 1018 cm-3 are approximately 7%. The time constants for degradation increase with increasing sulfur concentration, but not fast enough to be of practical importance in photovoltaic devices.

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