LPCVD Of Silicon Carbide Films From The Organosilanes Diethylsilane And Di-T-Butylsilane

1993 ◽  
Vol 306 ◽  
Author(s):  
Roland A. Levy ◽  
James M. Grow
Keyword(s):  
Silicon Carbide ◽  
Carbon Content ◽  
Optical Transmission ◽  
Reaction Chamber ◽  
Silicon Carbonitride ◽  
Film Stress ◽  
Transmission Characteristics ◽  
Free Standing ◽  
Excess Carbon ◽  
Optimal Processing

AbstractIn this paper, the kinetics and properties of amorphous LPCVD silicon carbide films synthesized from the single organosilane precursors diethylsilane (DES) or di-tbutylsilane (DTBS) are discussed. For DES, the growth rate is observed to vary linearly with flow rate and pressure, while for DTBS, a square root dependency is seen as a function of these parameters. An Arrhenius type behavior was observed for both chemistries yielding activation energy values of 40 and 25 kcal/mol for DES and DTBS respectively. The elemental composition of the films became progressively richer in carbon as the deposition temperature increased with stoichiometry occurring near 750°C. The film stress was dependent on carbon content and became compressive at compositions near Si0.35C0.65. The hardness and Young's modulus of the films increased with increasing carbon content reaching maxima near stoichiometry. Free-standing membranes produced under optimal processing conditions had a relatively low optical transmission due to excess carbon. Although, transmission characteristics were improved by adding NH3 in the reaction chamber, the resulting silicon carbonitride films exhibited undesirably high values of tensile stress.

TEM of grain growth and phase transformations during creep of SCS-6 silicon carbide fibers

1995 ◽  
Vol 53 ◽  
pp. 350-351
Author(s):  
L. A. Giannuzzi ◽  
C. A. Lewinsohn ◽  
C. E. Bakis ◽  
R. E. Tressler
Keyword(s):  
Silicon Carbide ◽  
Creep Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Primary Creep ◽  
Excess Carbon ◽  
Silicon Carbide Fibers ◽  
Sic Fiber ◽  
Carbon Core ◽  
Grain Width

The SCS-6 SiC fiber is a 142 μm diameter fiber consisting of four distinct regions of βSiC. These SiC regions vary in excess carbon content ranging from 10 a/o down to 5 a/o in the SiC1 through SiC3 region. The SiC4 region is stoichiometric. The SiC sub-grains in all regions grow radially outward from the carbon core of the fiber during the chemical vapor deposition processing of these fibers. In general, the sub-grain width changes from 50nm to 250nm while maintaining an aspect ratio of ~10:1 from the SiC1 through the SiC4 regions. In addition, the SiC shows a <110> texture, i.e., the {111} planes lie ±15° along the fiber axes. Previous has shown that the SCS-6 fiber (as well as the SCS-9 and the developmental SCS-50 μm fiber) undergoes primary creep (i.e., the creep rate constantly decreases as a function of time) throughout the lifetime of the creep test.

Influence of Carbon Content on Ceramic Injection Molding of Reaction-Bonded Silicon Carbide

2016 ◽  
Vol 13 (5) ◽  
pp. 838-843 ◽  
Author(s):  
Zhao Zhang ◽  
Yujun Zhang ◽  
Hongyu Gong ◽  
Xue Guo ◽  
Yubai Zhang ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Injection Molding ◽  
Carbon Content ◽  
Ceramic Injection Molding

Scanning Auger and Xps Studies of Fracture Surfaces of B4C Hot Pressed with Excess Carbon

1989 ◽  
Vol 153 ◽  
Author(s):  
Benjamin M. DeKoven ◽  
Eric A. Ness ◽  
David D. Hawn
Keyword(s):  
Fracture Surface ◽  
Boron Carbide ◽  
Carbon Content ◽  
Low Dose ◽  
Xps Spectra ◽  
Excess Carbon ◽  
Fracture Surfaces ◽  
Four Point Bending ◽  
Hardness Values

AbstractA series of boron carbide materials was hot pressed with 0-7% excess carbon. The strength of each material was determined by four point bending, and found to decrease from about 600MPa to 300MPa as the carbon content increased from 0% to 7%. Diamond indentation yielded hardness values that decreased from 28.3 to 25.OGPa and toughness values that increased from 3.5 to 4.5 MPa√mover the same carbon range. Each sample was fractured in situ in ultrahigh vacuum (UHV) and examined by scanning Auger microanalysis (SAM) and XPS to determine both the elemental and chemical state distributions. For the samples with excess carbon, localized carbonrich regions are observed on fracture surfaces by SAM. XPS reveals a 50% enhancement of excess carbon on the fracture surface compared to the bulk for the sample with 7% excess carbon. A correlation was observed between surface carbon composition and the bulk toughness and hardness. The C(ls) XPS spectra were utilized to determine the nature of carbon in B4C on freshly fractured and Ne+ bombarded surfaces. Two distinct peaks were observed in the C(ls) region. Low dose ion bombardment resulted in a single broad C(ls) peak at the midpoint of the two initial peaks. It can be inferred from this data that there are C-C-C intericosahedral linkages in B4C.

scholarly journals Origin of Doping in Quasi-Free-Standing Graphene on Silicon Carbide

2012 ◽  
Vol 108 (24) ◽  
Author(s):  
J. Ristein ◽  
S. Mammadov ◽  
Th. Seyller
Keyword(s):  
Silicon Carbide ◽  
Free Standing

Wide Bandgap Fluorinated Silicon-Carbide-Nitride Films Using NF3

1991 ◽  
Vol 219 ◽  
Author(s):  
H. C. Goh ◽  
S. M. Tan ◽  
H. A. Naseem ◽  
S. S. Ang ◽  
W. D. Brown
Keyword(s):  
Silicon Carbide ◽  
Refractive Index ◽  
Carbon Content ◽  
Power Density ◽  
Deposition Rate ◽  
Gas Flow ◽  
Substantial Reduction ◽  
Wide Bandgap ◽  
Amorphous Hydrogenated Silicon ◽  
Stainless Steel Reactor

ABSTRACTAmorphous hydrogenated silicon carbide has been studied extensively because of its properties as a wide bandgap material. However, a large amount of methane is needed to deposit the material. Also, the high carbon content of these films poses some problems. The addition of NF3 to the gas stream results in wide bandgap films with a substantial reduction in the required CH4 flow for deposition. Amorphous SiCx Ny :H:F films were prepared using rf glow discharge decomposition of silane, methane, and nitrogen trifluoride in a parallel-plate stainless steel reactor. Gas flow rate and power density were varied. For a gas mixture containing 6% NF3 and 78% CH4, FTIR measurements reveal a reduction in C-H peak heights at 2960 cm-1 and 2880 cm-1 with respect to the Si-H peak at 2080 cm-1 indicating a smaller carbon content in the film. The C-H peaks shift to higher wavenumbers with increasing NF3. The use of NF3 increases the bandgap from 2.6 to 3.14 eV while reducing the refractive index from 2.12. to 1.87. A maximum deposition rate of 625 A/min was achieved. This should be compared to the very low deposition rate of 18 A/min for comparable bandgap Si-C films deposited using 97% methane in silane. Increasing the deposition power density resulted in a larger bandgap and a smaller refractive index.

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