Possible role of oxygen impurities in degradation of nc-TiN∕a-Si[sub 3]N[sub 4] nanocomposites

Author(s):  
Stan Veprek ◽  
Pavla Karvankova ◽  
Maritza G. J. Veprek-Heijman
Keyword(s):  
1995 ◽  
Vol 378 ◽  
Author(s):  
R. J. Molnar ◽  
K. B. Nichols ◽  
P. Maki ◽  
E. R. Brown ◽  
I. Melngailis

AbstractGallium nitride (GaN) films grown by hydride vapor phase epitaxy on a variety of substrates have been investigated to study what role silicon and oxygen impurities play in determining the residual donor levels found in these films. Secondary ion mass spectroscopy analysis has been performed on these films and impurity levels have been normalized to ion implanted calibration standards. While oxygen appears to be a predominate impurity in all of the films, in many of them the sum of silicon and oxygen levels is insufficient to account for the donor concentration determined by Hall measurements. This suggests that either another impurity or a native defect is at least partly responsible for the autodoping of GaN. Additionally, the variation of impurity and carrier concentration with surface orientation and/or nucleation density suggests either a crystallographic or defect-related incorporation mechanism.


2009 ◽  
Vol 105 (12) ◽  
pp. 123508 ◽  
Author(s):  
C. A. Londos ◽  
A. Andrianakis ◽  
V. Emtsev ◽  
H. Ohyama

1990 ◽  
Vol 5 (1) ◽  
pp. 218-222 ◽  
Author(s):  
Jeffrey R. Lince

The chemical composition and structure of MoS2 solid lubricant films are intimately related to their friction and wear characteristics. We have conducted an x-ray photoelectron spectroscopy (XPS) study of 1-μm thick radio frequency (rf)-sputter-deposited MoS2 films to determine the chemical state of the films, focusing on the role of oxygen impurities. Concentrations of chemisorbed and bulk species were determined from the Mo 3d, S 2p, and O 1s peak shapes and intensities after annealing the films to temperatures from 425 to 975 K. Films deposited on substrates that were at ∼345 K [ambient temperature (AT) films] and on substrates heated to ∼525 K [high temperature (HT) films] both had ∼10% oxygen within the bulk of the films. The relative areas and shapes of the XPS peaks for the HT films at all annealing temperatures were consistent with the formation of a MoS2−xOx solid solution, where O atoms were probably substituted into S sites in the 2H–MoS2 crystal lattice. In AT films, this phase composition was stable only for annealing temperatures ≥725 K, in agreement with previous studies of the changes in crystal structure of AT films with annealing. The results are discussed in terms of previous studies of the structure and composition of sputter-deposited MoS2 films.


1996 ◽  
Vol 449 ◽  
Author(s):  
Jai-Young Lee ◽  
Yoon-Joong Yong

ABSTRACTHydrogenated aluminum nitride (A1N:H) films have been deposited on the (100) silicon wafers by the RF reactive magnetron sputtering method with H2 gas in addition to an Ar-N2 gas mixture. Stoichiometric A1N films without oxygen impurities can be prepared by adding 10 % H2 to reactive gas, which is proven by Rutherford Backscattering Spectrometry (RBS). The bonding aspects of Al, N, O and H atoms in A1N:H films have been examined by X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared (FTIR) to understand the effects of H2 addition. The chemical shift of the binding energies of A1, N and O atoms in A1N:H films from XPS analysis and the change of N-H bonding in FTIR with respect to different partial pressures of H2 gas have been confirmed. The role of H atoms is suggested to facilitate bonding with unbound N atoms in A1N:H films and hinder N-O bonding, thus, reducing oxygen concentration in A1N:H films. Also, the activation energy for the evolution of H2 gas from A1N:H film has been determined to be 0.11 eV/atom through a Kissinger-type analysis by a thermal desorption test using Gas Chromatograph(GC). This result implies that the hydrogen atom in film forms the hydrogen bond.


2008 ◽  
Vol 26 (3) ◽  
pp. 313-320 ◽  
Author(s):  
Stan Veprek ◽  
Chunlin Wang ◽  
Maritza G. J. Veprek-Heijman

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