A Multiple Quantum NMR (MQNMR) Study of Hydrogen Microstructure in Boron Doped a-Si:H

1992 ◽  
Vol 258 ◽  
Author(s):  
S. Mitra ◽  
D. H. Levy ◽  
K. K. Gleason ◽  
H. Jia ◽  
J. Shinar
Keyword(s):  
Boron Content ◽  
Secondary Ion Mass Spectrometry ◽  
Multiple Quantum ◽  
Moderate Increase ◽  
Preparation Time ◽  
Boron Doped ◽  
Three Samples ◽  
Secondary Ion ◽  
Weakly Dependent ◽  
Multiple Quantum Nmr

ABSTRACTAn IR and multiple quantum NMR (MQNMR) study of hydrogen microstructure in three boron doped a-Si:H is discussed. The total Si-bonded H content of all films was 6.5 ± 1.0 at.% as determined by the 640 cm-1 IR wagging mode, but their boron content, which was determined by secondary ion mass spectrometry, ranged from 0.02 to 0.3 at. %. The number of correlated hydrogen, as measured at a preparation time of 600 μSwas found to be more weakly dependent on the boron content than previously observed in phosphorous-doped glow-discharge films. Upon annealing at 220 °C the MQNMR spectrum show a moderate increase in the number of correlated hydrogen in all three samples.

scholarly journals Disordering of InGaN/GaN Superlattices After High-Pressure Annealing

1998 ◽  
Vol 537 ◽  
Author(s):  
M.D. McCluskey ◽  
L.T. Romano ◽  
B.S. Krusor ◽  
D. Hofstetter ◽  
D.P. Bour ◽  
...  
Keyword(s):  
Quantum Well ◽  
Secondary Ion Mass Spectrometry ◽  
Multiple Quantum Well ◽  
Blue Shift ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Temperatures ◽  
Composition Profiles ◽  
Secondary Ion

AbstractInterdiffusion of In and Ga is observed in InGaN multiple-quantum-well superlattices for annealing temperatures of 1250 to 1400°C. Hydrostatic pressures of up to 15 kbar were applied during the annealing treatments to prevent decomposition of the InGaN and GaN. In as-grown material, x-ray diffraction spectra show InGaN superlattice peaks up to the fourth order. After annealing at 1400°C for 15 min, only the zero-order InGaN peak is observed, a result of compositional disordering of the superlattice. Composition profiles from secondary ion mass spectrometry indicate significant diffusion of Mg from the p-type GaN layer into the quantum well region. This Mg diffusion may lead to an enhancement of superlattice disordering. For annealing temperatures between 1250 and 1300°C, a blue shift of the InGaN spontaneous emission peak is observed, consistent with interdiffusion of In and Ga in the quantum-well region.

IR and Sims Study of Hydrogen Diffusion in RF Sputter Deposited Boron Doped a-Si:H and Undoped a-Ge:H

1989 ◽  
Vol 149 ◽  
Author(s):  
S. Mitra ◽  
X.-L. Wu ◽  
R. Shinar ◽  
J. Shinar
Keyword(s):  
Hydrogen Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Stretch Vibration Band ◽  
Vibration Band ◽  
Boron Doped ◽  
Multiple Trapping ◽  
Stretch Vibration ◽  
Order Of Magnitude ◽  
Sputter Deposited ◽  
Secondary Ion

ABSTRACTSecondary ion mass spectrometry (SIMS) and IR measurements of long range deuterium motion in rf sputter deposited (rf sp) p-doped a-Si:H and undoped a-Ge:H are compared to recently published results on undoped rf sp a-Si:H, which exhibited strongly power-law time dependent diffusion constants (exponent α= 0.75±0.1) in films of as-deposited content of di-H and tri-H bonds (usually associated with microvoids) Ndo –4–5 at.%. In pdoped a-Si:H samples where Ndo-l.8–3.8at.%, the diffusion is much faster, but the exponent is similar. In undoped a-Ge:H exhibiting a stretch vibration band indicative of mono-H bonding only, the diffusion is about one order of magnitude faster than in undoped a-Si:H, and α = 0.23. The results are discussed in relation to both the multiple trapping (dispersive) and defect mediated diffusion models.

Investigation of the Dopant Distribution in thin Epitaxial Silicon Layers by Means of Spreading Resistance Probe and Secondary Ion Mass Spectrometry

1997 ◽  
Vol 500 ◽  
Author(s):  
Ilya Karpov ◽  
Catherine Hartford ◽  
Greg Moran ◽  
Subramania Krishnakumar ◽  
Ron Choma ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Vapor ◽  
Doping Profile ◽  
Epitaxial Silicon ◽  
Spreading Resistance ◽  
Boron Doped ◽  
Ion Mass Spectrometry ◽  
Chemical Profiles ◽  
Secondary Ion

ABSTRACTIn this paper, we examine the dopant distributions in 1.8 to 4 micron-thick boron- and phosphorus-doped epitaxial silicon layers. These layers were grown by chemical vapor deposition (CVD) on arsenic-, antimony-, or boron-doped (100)- and (111)-oriented substrates. We performed doping profile studies by means of local resistivity measurements using a spreading resistance probe (SRP). Chemical profiles of the dopants were also obtained using secondary ion mass spectrometry (SIMS).

Microstructure and Hydrogen Dynamics in a-Si1-xCx:H

1999 ◽  
Vol 557 ◽  
Author(s):  
R. Shinar ◽  
J. Shinar ◽  
D. L. Williamson ◽  
S. Mitra ◽  
H. Kavak ◽  
...  
Keyword(s):  
Electron Cyclotron Resonance ◽  
Secondary Ion Mass Spectrometry ◽  
Total Content ◽  
Relaxation Processes ◽  
Fast Diffusion ◽  
X Ray Scattering ◽  
Boron Doped ◽  
Sputter Deposited ◽  
Hydrogenated Amorphous ◽  
Secondary Ion

AbstractSmall angle x-ray scattering (SAXS), IR spectroscopy, and deuterium secondary ion mass spectrometry (DSIMS) were used to study the microstructure and hydrogen dynamics of undoped and boron-doped if-sputter-deposited (RFS) and electron cyclotron resonance (ECR)-deposited hydrogenated amorphous silicon carbides (a-Si1-xCx:H) with x ≤ 19 at.%. The SAXS measurements indicated residual columnar-like features and roughly spherical nanovoids of total content CnV ≤ 1.0 vol.%. The growth of CnV with annealing was due largely to an increase in the average nanovoid radius. It was noticeably smaller than in RFS a-Si:H films. The IR spectra demonstrated H transfer by annealing from mostly bulk-like Si-H groups to C-bonds. The H diffusion and its temperature dependence in undoped films resembled those of a-Si:H and were consistent with the SAXS and IR data. Suppression of long-range motion of most of the H atoms, consistent with increased CnV was observed in B-doped ECR films. However, a small fraction of the H atoms appeared to undergo fast diffusion, reminiscent of the fast diffusion in doped a-Si:H. The results are consistent with impeded relaxation processes of the Si network, caused by the presence of C atoms, and H trapping at C-H bonds.

scholarly journals Disordering of InGaN/GaN Superlattices after High-Pressure Annealing

1999 ◽  
Vol 4 (S1) ◽  
pp. 293-298
Author(s):  
M.D. McCluskey ◽  
L.T. Romano ◽  
B.S. Krusor ◽  
D. Hofstetter ◽  
D.P. Bour ◽  
...  
Keyword(s):  
Quantum Well ◽  
Secondary Ion Mass Spectrometry ◽  
Multiple Quantum Well ◽  
Blue Shift ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Temperatures ◽  
Composition Profiles ◽  
Secondary Ion

Interdiffusion of In and Ga is observed in InGaN multiple-quantum-well superlattices for annealing temperatures of 1250 to 1400°C. Hydrostatic pressures of up to 15 kbar were applied during the annealing treatments to prevent decomposition of the InGaN and GaN. In as-grown material, x-ray diffraction spectra show InGaN superlattice peaks up to the fourth order. After annealing at 1400°C for 15 min, only the zero-order InGaN peak is observed, a result of compositional disordering of the superlattice. Composition profiles from secondary ion mass spectrometry indicate significant diffusion of Mg from the p-type GaN layer into the quantum well region. This Mg diffusion may lead to an enhancement of superlattice disordering. For annealing temperatures between 1250 and 1300°C, a blue shift of the InGaN spontaneous emission peak is observed, consistent with interdiffusion of In and Ga in the quantum-well region.

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.

Influence of Substrate Temperature on the Properties of A-Si:H P-Layers Obtained from Trimethylboron

1994 ◽  
Vol 336 ◽  
Author(s):  
J. Puigdollers ◽  
J.M. Asensi ◽  
J. Bertomeu ◽  
J. Andreu ◽  
J.C. Delgado
Keyword(s):  
Substrate Temperature ◽  
Optical Transmission ◽  
Boron Content ◽  
Secondary Ion Mass Spectrometry ◽  
Dark Conductivity ◽  
Film Properties ◽  
Atom Concentration ◽  
Influence Of Substrate ◽  
Secondary Ion ◽  
Marked Dependence

ABSTRACTa-Si:H p-layers doped by trimethylboron (TMB) were obtained by PECVD in a monochamber reactor with a rotating substrate holder. The influence of the substrate temperature (Ts) on the film properties was systematically studied for two different doping gas concentrations. The incorporation of boron, hydrogen and carbon was studied by Secondary Ion Mass Spectrometry (SIMS). Optical properties were determined by means of Photothermal Deplection Spectroscopy (PDS) and optical transmission. Dark conductivity (aj and activation energy (Eact) were measured electrically. Our results show that Σd has a marked dependence on substrate temperature, although boron atom concentration depends only slightly on Ts. The optical gap for samples obtained at the higher concentration also depends on Ts and its dependence is related to the hydrogen content, as boron content does not change. P-i-n diodes were obtained with the p-layer deposited from TMB.

An Explanation for the Environmental Sensitivity of Ni3Al

1998 ◽  
Vol 552 ◽  
Author(s):  
D. B. Lillig ◽  
D. Legzdina ◽  
I. M. Robertson ◽  
H. K. Birnbaum
Keyword(s):  
Mass Spectrometry ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Secondary Ion Mass Spectrometry ◽  
Environmental Sensitivity ◽  
Boron Segregation ◽  
Boron Doped ◽  
Distribution Of Elements ◽  
Free Material ◽  
Secondary Ion

ABSTRACTSecondary Ion Mass Spectrometry has been used to study the distribution of elements in and near grain boundaries in boron-free and boron-doped Ni76Al24 alloys with and without ∼220 wt. ppm of deuterium. In boron-free alloys, sulfur was distributed about the grain boundaries in both deuterium- free and deuterium-charged samples. The distribution of deuterium followed that of sulfur and was segregated to grain boundaries. In the boron-doped material, sulfur was not found at most grain boundaries in the uncharged material, but was in the charged material. No deuterium was found at the grain boundaries in the boron-doped material. It is proposed that in the boron-free material it is the synergistic effect of sulfur and hydrogen that is responsible for the environmental sensitivity of this alloy. In boron-doped material, boron segregation to the grain boundary prevents sulfur, and to some extent hydrogen, segregating to the grain boundary.

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