Deposition of Device Quality, Low H Content a-Si:H by the Hot Wire Technique

1991 ◽  
Vol 219 ◽  
Author(s):  
A. H. Mahan ◽  
B. P. Nelson ◽  
S. Salamon ◽  
R. S. Crandall
Keyword(s):  
Chemical Vapor ◽  
Hot Wire ◽  
X Ray ◽  
Quality Properties ◽  
X Ray Scattering ◽  
Structural Differences ◽  
Rf Glow Discharge ◽  
First Time ◽  
Hydrogenated Amorphous ◽  
Traditional Manner

ABSTRACTWe report measurements of the Urbach edge, optical bandgap, and ambipolar diffusion length on a series of hydrogenated amorphous silicon (a-Si:H) films deposited by hot-wire-assisted chemical vapor deposition (HW). We compare the properties of these films to those of a series of a-Si:H films deposited by the traditional radio frequency (rf) glow discharge (GD) technique, where we varied the substrate temperature to change the bonded H content (CH). We show for the first time that, as CH is decreased below the value traditionally associated with device quality GD a-Si:H (∼10 at.%), the electronic properties of the GD films deteriorate in the traditional manner while those for the HW samples remain device quality. Properties of these low CH HW samples will be presented and compared to those of GD films containing comparable CH. Because several indications exist that the structure of the HW films is different than that of the GD films, Raman and Small Angle X-Ray Scattering (SAXS) measurements are presented to illustrate structural differences.

XRR and SAXS Study of Hydrogenated Amorphous Silicon Oxycarbide (a-SiOC:H) Films

2007 ◽  
Vol 561-565 ◽  
pp. 1247-1250 ◽  
Author(s):  
Bibhu P. Swain
Keyword(s):  
Photoelectron Spectroscopy ◽  
Large Scale ◽  
Silicon Oxide ◽  
Chemical Vapor ◽  
Silicon Oxycarbide ◽  
Hydrogenated Silicon ◽  
X Ray ◽  
Pure Silicon ◽  
X Ray Scattering ◽  
Hydrogenated Amorphous

Thin films of hydrogenated silicon-oxycarbide (a-SiOCx:H) have largely replaced pure silicon oxide films as back end of line (BEOL) processing in Ultra Large Scale Integrate Circuit (ULSI). A single chamber system for hot wire chemical vapor deposition (HWCVD) was employed to deposit different films of a-SiOCx:H with 0.5 < x < 0.8. All films were characterized by infrared spectroscopy and X-ray photoelectron spectroscopy (XPS) to determine the stoichiometry and the presence of various bonding configurations of constituent atoms. We used X-ray reflectivity (XRR) and Small angle X- ray scattering (SAXS) to determine the porosity and inhomogeneities (clustering) in the films.

Films and Devices Deposited by Hwcvd at Ultra High Deposition Rates

2001 ◽  
Vol 664 ◽  
Author(s):  
A. H. Mahan ◽  
Y. Xu ◽  
E. Iwaniczko ◽  
D. L. Williamson ◽  
W. Beyer ◽  
...  
Keyword(s):  
Defect Density ◽  
State Of The Art ◽  
Chemical Vapor ◽  
Film Deposition ◽  
Hot Wire ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Film Deposition Rate ◽  
Staebler Wronski Effect

ABSTRACTThe structure of a-Si:H, deposited at rates in excess of 100Å/s by the hot wire chemical vapor deposition (HWCVD) technique, has been examined by x-ray diffraction (XRD), Raman spectroscopy, H evolution, and small-angle x-ray scattering (SAXS). As the film deposition rate (Rd) is increased, we find that the XRD, Raman and the H evolution peak curves are invariant with Rd, and exhibit structure consistent with state-of-the-art, compact a-Si:H films deposited at low Rd. The only exception is the SAXS signal, which increases by a factor of ∼100 over that for our best low Rd films. We relate changes in the film electronic structure (Urbach edge) to the increase in the SAXS signals. We also note the invariance of the saturated defect density versus Rd, and discuss possible reasons why the increase in the SAXS does not play a role in the Staebler-Wronski Effect for this type of material. Finally, device results are presented.

Mesoscopic structure of SiC fibers by neutron and x-ray scattering

1996 ◽  
Vol 11 (5) ◽  
pp. 1169-1178 ◽  
Author(s):  
Kentaro Suzuya ◽  
Michihiro Furusaka ◽  
Noboru Watanabe ◽  
Makoto Osawa ◽  
Kiyohito Okamura ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Volume Fraction ◽  
X Rays ◽  
X Ray ◽  
Sic Fibers ◽  
X Ray Scattering ◽  
Mesoscopic Structure ◽  
Angle Scattering ◽  
Momentum Transfer Range ◽  
First Time

Mesoscopic structures of SiC fibers produced from polycarbosilane by different methods were studied by diffraction and small-angle scattering of neutrons and x-rays. Microvoids of a size of 4–10 Å in diameter have been observed for the first time by neutron scattering in a medium momentum transfer range (Q = 0.1–1.0 Å−1). The size and the volume fraction of β–SiC particles were determined for fibers prepared at different heat-treatment temperatures. The results show that wide-angle neutron scattering measurements are especially useful for the study of the mesoscopic structure of multicomponent materials.

Influence of high energy electron irradiation on the network structure of gelatin hydrogels as investigated by small-angle X-ray scattering (SAXS)

2017 ◽  
Vol 19 (19) ◽  
pp. 12064-12074 ◽  
Author(s):  
Emilia I. Wisotzki ◽  
Paolo Tempesti ◽  
Emiliano Fratini ◽  
Stefan G. Mayr
Keyword(s):  
Electron Irradiation ◽  
Network Structure ◽  
Small Angle ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
X Ray ◽  
X Ray Scattering ◽  
Structural Differences ◽  
Ray Scattering

Small-angle X-ray scattering revealed ranging structural differences in physically entangled and irradiation-crosslinked gelatin hydrogels.

Stress in Hydrogenated Microcrystalline Silicon Thin Films

1999 ◽  
Vol 557 ◽  
Author(s):  
D. Peiró ◽  
C. Voz ◽  
J. Bertomeu ◽  
J. Andreu ◽  
E. Martínez ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vapor Deposition ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Hot Wire ◽  
X Ray Diffraction ◽  
Microcrystalline Silicon ◽  
X Ray ◽  
Silicon Thin Films ◽  
Abrupt Changes

AbstractHydrogenated microcrystalline silicon films have been obtained by hot-wire chemical vapor deposition (HWCVD) in a silane and hydrogen mixture at low pressure (<5 × 10-2 mbar). The structure of the samples and the residual stress were characterised by X- ray diffraction (XRD). Raman spectroscopy was used to estimate the volume fraction of the crystalline phase, which is in the range of 86 % to 98%. The stress values range between 150 and -140 MPa. The mechanical properties were studied by nanoindentation. Unlike monocrystalline wafers, there is no evidence of abrupt changes in the force-penetration plot, which have been attributed to a pressure-induced phase transition. The hardness was 12.5 GPa for the best samples, which is close to that obtained for silicon wafers.

Structural Differences of Ovalbumin and S-Ovalbumin Revealed by Denaturing Conditions

1997 ◽  
Vol 52 (9-10) ◽  
pp. 645-653 ◽  
Author(s):  
Corrado Paolinelli ◽  
Mario Barteri ◽  
Federico Boffi ◽  
Francesca Forastieri ◽  
Maria Cristina Gaudiano ◽  
...  
Keyword(s):  
Experimental Data ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Guanidine Hydrochloride ◽  
Stable Form ◽  
X Ray ◽  
Heat Stable ◽  
X Ray Scattering ◽  
Structural Differences ◽  
Circular Dichroïsm

We found, by circular dichroism and Raman spectroscopy measurements, that the secondary structure of the native ovalbumin and of its heat-stable form, called S-ovalbumin, is a probe of the structural differences between the two proteins. Small angle X-ray scattering and circular dichroism measurements performed on the two proteins under denaturing conditions, with different concentrations of guanidine hydrochloride, show the changes of the tertiary and secondary structure and a different pathway in the unfolding process. These experimental data confirm that the conversion of native ovalbumin into S-ovalbumin is irreversible and reveal that the response of the two proteins to the same chemical environment is different

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