Ultra Thin SiNX on a-Si In Situ Hot-Wire CVD by Decomposing NH3 Gas

2014 ◽  
Vol 894 ◽  
pp. 421-426
Author(s):  
Dharmendra Kumar R. Rai ◽  
Dayanand S. Sutar ◽  
Chetan Singh Solanki ◽  
K.R. Balasubramaniam
Keyword(s):  
Raman Spectroscopy ◽  
Silicon Nitride ◽  
Photoelectron Spectroscopy ◽  
Profile Measurement ◽  
Hot Wire ◽  
X Ray ◽  
Superlattice Structures ◽  
Xps Depth Profile ◽  
Si Wafer

The fabrication of ultra thin silicon nitride (SiNX) layer (< 2 nm) on amorphous silicon (a-Si) in-situ hot-wire CVD by decomposing ammonia (NH3) gas is reported. Approximately 1.5 nm thin SiNXis formed by nitridation of 40 nm thick a-Si for 10 min at substrate temperature of 250 °C. The amorphous phase of SiNXformed on a-Si and a-Si layer deposited on c-Si wafer is identified by Raman spectroscopy. The formation of ultra thin SiNXby nitridation of a-Si at 250 °C is confirmed by X-ray photoelectron spectroscopy (XPS) depth profile measurement of SiNX/a-Si structured film. The report indicates that the HWCVD method can be used for fabricating superlattice structures consisting of ultra thin SiNXlayers (< 2 nm).

scholarly journals In-Situ X-ray Photoelectron Spectroscopy and Raman Microscopy of Roselite Crystals, Ca2(Co2+,Mg)(AsO4)2 2H2O, from the Aghbar Mine, Morocco

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 670
Author(s):  
Jacob Teunis Kloprogge ◽  
Barry James Wood ◽  
Danilo Octaviano Ortillo
Keyword(s):  
Raman Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Raman Microscopy ◽  
Antisymmetric Mode ◽  
Crystal Water ◽  
X Ray ◽  
Bending Modes ◽  
Symmetric And Antisymmetric Modes ◽  
Lattice Modes

Roselite from the Aghbar Mine, Morocco, [Ca2(Co2+,Mg)(AsO4)2 2H2O], was investigated by X-ray Photoelectron and Raman spectroscopy. X-ray Photoelectron Spectroscopy revealed a cobalt to magnesium ratio of 3:1. Magnesium, cobalt and calcium showed single bands associated with unique crystallographic positions. The oxygen 1s spectrum displayed two bands associated with the arsenate group and crystal water. Arsenic 3d exhibited bands with a ratio close to that of the cobalt to magnesium ratio, indicative of the local arsenic environment being sensitive to the substitution of magnesium for cobalt. The Raman arsenate symmetric and antisymmetric modes were all split with the antisymmetric modes observed around 865 and 818 cm−1, while the symmetric modes were found around 980 and 709 cm−1. An overlapping water-libration mode was observed at 709 cm−1. The region at 400–500 cm−1 showed splitting of the arsenate antisymmetric mode with bands at 499, 475, 450 and 425 cm−1. The 300–400 cm−1 region showed the corresponding symmetric bending modes at 377, 353, 336 and 304 cm−1. The bands below 300 cm−1 were assigned to lattice modes.

X-Ray Photoelectron Spectroscopy of In-Situ Fractured Reaction Bonded Silicon Nitride

1985 ◽  
Vol 60 ◽  
Author(s):  
M. S. Donley ◽  
T. G. Stoebe ◽  
M. T. Thomas
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Photoelectron Spectroscopy ◽  
Iron Species ◽  
Metallurgical Grade Silicon ◽  
X Ray ◽  
Grade Silicon ◽  
Boundary Chemistry

AbstractThe grain boundary chemistry of reaction bonded silicon nitride (RBSN) and the effects of iron species and content on this chemistry are investigated using X-ray photoelectron spectroscopy (XPS). Data are reported for semiconductor grade RBSN, Fe-doped semiconductor grade RBSN, and metallurgical grade RBSN specimens. Results indicate that the grain boundaries have an elemental composition of Si, N, O, and C, with important chemical differences depending on the purity of the starting material. In the RBSN made from metallurgical grade silicon, the grain boundaries have a distinct “oxide-like” layer, with a subregion of Si3N4. No distinct oxide layer was observed in the RBSN made from semiconductor-grade silicon, where the O appears to be uniformly incorporated into the Si3N4.

scholarly journals In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Marc Benjamin Hahn ◽  
Paul M. Dietrich ◽  
Jörg Radnik
Keyword(s):  
Dna Damage ◽  
Radiation Damage ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
In Situ Monitoring ◽  
Strong Increase ◽  
Oh Radicals ◽  
Strand Breaks ◽  
X Ray

AbstractIonizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.

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