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.

Comparative Study of Hydrogen Diffusion in Hot-Wire and Glow-Discharge-Deposited a-Si:H

1999 ◽  
Vol 557 ◽  
Author(s):  
J. Shinar ◽  
R. Shinar ◽  
K. E. Junge ◽  
E. Iwaniczko ◽  
A. H. Mahan ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Hydrogen Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Error Function ◽  
Interface Layer ◽  
Hot Wire ◽  
Release Times ◽  
Multiple Trapping ◽  
Complementary Error Function ◽  
Secondary Ion

AbstractLong-range atomic H motion in hot-wire deposited (HW) a-Si:H is compared directly to that in glow-discharge deposited (GD) a-Si:H by monitoring the deuterium secondary ion mass spectrometry (DSLMS) profiles in [GD a-Si:H]/[GD a-Si:(H,D)]/[HW a-Si:H] multilayers vs annealing temperature and time. While the profiles in the GD layer are in excellent agreement with complementary error-function behavior and previous studies, the profiles in the HW layer suggest that the multiple-trapping motion of the H and D atoms is much slower, possibly due to an interface layer of defects. However, an exponential “tail” of D atoms extends deep into the HW layer, probably due to a long diffusion length of mobile D atoms, consistent with the established release times of H and D from the GD layer and H loss typical during growth of HW films. The results are also discussed in terms of the H exchange model and compared to previous NMIR studies of HW a-Si:H, which suggest that most of the hydrogen in the HW layer is concentrated in H-rich clusters dispersed in a network of very low H content.

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.

Hydrogen Diffusion in Undoped and B-Doped a-Si1-xCx:H

1994 ◽  
Vol 336 ◽  
Author(s):  
R. Shinar ◽  
J. Shinar ◽  
G. Subramania ◽  
H. Jia ◽  
S. Sankaranarayanan ◽  
...  
Keyword(s):  
Hydrogen Diffusion ◽  
Electron Cyclotron Resonance ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Constant ◽  
Fast Diffusion ◽  
Carrier Recombination ◽  
Boron Doped ◽  
Stretch Vibration ◽  
B Doping ◽  
Resonance Plasma

ABSTRACTA deuterium secondary ion mass spectrometry (SIMS) study of hydrogen diffusion in undoped and boron-doped a-Si0.86C0.4:H deposited by an electron cyclotron resonance plasma is described. The undoped films deposited at 250°C clearly indicated deuterium-hydrogen interdiffusion at T ≥ 350°C. The dispersion parameter a of the power-law time dependent diffusion constant D = D00(ωt)−α decreased from ∼0.3 at T = 350 and 400°C to ∼0.1 at 450°C, and the activation energy for a diffusion length of 1000 Å was ∼1.0 eV. These results are discussed in relation to previous studies of a-Si:H. The diffusion in ∼0.2 and ∼0.6 at.% B-doped a-Si0.86C0.14:H sharply differs from that in B-doped a-Si:H, where an enhancement of up to ∼103 was previously observed. In doped a-Si0.86C0.14:H, the diffusion of most of the H atoms is strongly suppressed, but a small fraction undergoes fast diffusion. IR Measurements indicate that the B-doping reduces the bulk-like Si-H stretch vibration at ∼2000 cm1. Upon annealing, the Si-CHn and C-H wag modes at ∼780 and ∼1000 cm−1, resp., increase, while the 640 and ∼2000 cm1 Si-H wag and stretch modes, resp., weaken, indicating transfer of hydrogen from Si- to C-bonds, in which the H atoms are apparently deeply trapped. As in a-Si:H, the fast diffusion component is apparently due to carrier recombination-enhanced weak Si-Si bond breaking. The results suggest that B-doping also induces microvoids and enhances the rate of breaking of weak Si-C bonds, leading to enhanced trapping of H.

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).

Hydrogen diffusion in polycrystalline boron doped and undoped diamond.

2004 ◽  
Vol 813 ◽  
Author(s):  
D. Ballutaud ◽  
A. Boutry-Forveille ◽  
J.-M. Laroche ◽  
N. Simon ◽  
H. Girard ◽  
...  
Keyword(s):  
Hydrogen Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Tracer Diffusion ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Different Temperatures ◽  
Hydrogen Deuterium ◽  
Hot Filament

ABSTRACTHydrogen (deuterium used as tracer) diffusion experiments were performed on undoped and boron doped diamond films ([B] = 1019and 1020 cm−3) grown by plasma CVD or hot-filament assisted CVD. The samples were exposed either to a radiofrequency plasma or a microwave plasma at different temperatures between 400°C and 900°C. The deuterium profiles were analysed by secondary ion mass spectrometry (SIMS). The deuterium diffusion was explained mainly in term of trapping on intergranular defects. The passivation of boron acceptors, by B-D complex formation in the deuterium diffused superficial layers of the diamond films, was followed by electrochemical and mercury probe capacitance measurements. The results suggest a strong decrease of the free carrier density, which is in accordance with passivation of free carriers by deuterium trapping on dopant.

The study of carbon incorporation during growth in epitaxial indium antimonide layers prepared by metalorganic magnetron sputtering

1989 ◽  
Vol 67 (4) ◽  
pp. 298-303 ◽  
Author(s):  
T. Sudersena Rao ◽  
James B. Webb ◽  
J. P. Noad ◽  
J. Jackman
Keyword(s):  
Magnetron Sputtering ◽  
Indium Antimonide ◽  
Electron Spectroscopy ◽  
Secondary Ion Mass Spectrometry ◽  
Methyl Radicals ◽  
Carbon Impurities ◽  
Background Impurity ◽  
Order Of Magnitude ◽  
Secondary Ion ◽  
Deposition Conditions

Secondary-ion mass spectrometry and Auger electron spectroscopy measurements combined with Hall data have indicated high levels of electrically active carbon impurities in InSb films grown by metalorganic magnetron sputtering. Background impurity concentrations in the range of 5 × 1018 cm−3 were observed for films grown at optimum deposition conditions. While it was also observed that the level of carbon in the layers decreased with increasing substrate temperature and V-III ratio, the addition of small amounts of molecular hydrogen (H2) to the sputtering gas resulted in an order of magnitude decrease in the carbon content of the as-grown InSb layers. Mass spectrometric studies suggest that the major source of carbon contamination in the layers is the methyl radicals produced from the pyrolysis of trimethylindium.

Hydrogen Dynamics and Tee Distribution of H Sites in Undoped a-Si:H and a-Ge:H

1991 ◽  
Vol 219 ◽  
Author(s):  
R. Shinar ◽  
X.-L. Wu ◽  
S. Mitra ◽  
J. Shinar
Keyword(s):  
Mass Spectrometry ◽  
Activation Energy ◽  
Long Range ◽  
Secondary Ion Mass Spectrometry ◽  
Ir Studies ◽  
Multiple Trapping ◽  
Ion Mass Spectrometry ◽  
Secondary Ion ◽  
Trapping Sites

ABSTRACTSecondary ion mass spectrometry and IR studies of long-range hydrogen motion in undoped a-Si:H and a-Ge:H of varying H content and microstructure are reviewed and discussed. In particular, their relation to the multiple trapping (MT) model, the role of microvoids, the significance of the Meyer-Neldel relation (MNR), and the nature of H sites is addressed. It is suggested that while the MT mechanism may be significant in a-Si:H of low H content Cfj, it is largely marginal in films where CH ≥ 10 at.% H and in a-Ge:H. Mono Si-H bonds on microvoid surfaces are apparently deep H trapping sites up to ∼ 400°C, but H is desorbed from such sites in a-Ge:H above 180°C. The MNR between the diffusional activation energy and prefactor is observed among the various a-Si:H and a-Ge:H, but its significance is questionable, and may be due to the MT mechanism only in low H content a-Si:H. The nature of the distribution of H sites is also discussed.

scholarly journals Distribution of chlorine and fluorine in benthic foraminifera

2020 ◽  
Vol 17 (18) ◽  
pp. 4727-4743
Author(s):  
Anne Roepert ◽  
Lubos Polerecky ◽  
Esmee Geerken ◽  
Gert-Jan Reichart ◽  
Jack J. Middelburg
Keyword(s):  
Organic Molecules ◽  
Secondary Ion Mass Spectrometry ◽  
Environmental Parameters ◽  
Benthic Species ◽  
Shell Chemistry ◽  
Order Of Magnitude ◽  
Fundamental Insight ◽  
First Time ◽  
Secondary Ion ◽  
Insight Into

Abstract. Over the last few decades, a suite of inorganic proxies based on foraminiferal calcite have been developed, some of which are now widely used for palaeoenvironmental reconstructions. Studies of foraminiferal shell chemistry have largely focused on cations and oxyanions, while much less is known about the incorporation of anions. The halogens fluoride and chloride are conservative in the ocean, which makes them candidates for reconstructing palaeoceanographic parameters. However, their potential as a palaeoproxy has hardly been explored, and fundamental insight into their incorporation is required. Here we used nanoscale secondary ion mass spectrometry (NanoSIMS) to investigate, for the first time, the distribution of Cl and F within shell walls of four benthic species of foraminifera. In the rotaliid species Ammonia tepida and Amphistegina lessonii, Cl and F were distributed highly heterogeneously within the shell walls, forming bands that were co-located with the bands observed in the distribution of phosphorus (significant positive correlation of both Cl and F with P; p<0.01). In the miliolid species Sorites marginalis and Archaias angulatus, the distribution of Cl and F was much more homogeneous without discernible bands. In these species, Cl and P were spatially positively correlated (p<0.01), whereas no correlation was observed between Cl and F or between F and P. Additionally, their F content was about an order of magnitude higher than in the rotaliid species. The high variance in the Cl and F content in the studied foraminifera specimens could not be attributed to environmental parameters. Based on these findings, we suggest that Cl and F are predominately associated with organic linings in the rotaliid species. We further propose that Cl may be incorporated as a solid solution of chlorapatite or may be associated with organic molecules in the calcite in the miliolid species. The high F content and the lack of a correlation between Cl and F or P in the miliolid foraminifera suggest a fundamentally different incorporation mechanism. Overall, our data clearly show that the calcification pathway employed by the studied foraminifera governs the incorporation and distribution of Cl, F, P, and other elements in their calcite shells.

scholarly journals Distribution of chlorine and fluorine in benthic foraminifera

2019 ◽  
Author(s):  
Anne Roepert ◽  
Lubos Polerecky ◽  
Esmee Geerken ◽  
Gert-Jan Reichart ◽  
Jack J. Middelburg
Keyword(s):  
Mass Spectrometry ◽  
Organic Molecules ◽  
Secondary Ion Mass Spectrometry ◽  
Environmental Parameters ◽  
Benthic Species ◽  
Shell Chemistry ◽  
Order Of Magnitude ◽  
Fundamental Insight ◽  
First Time ◽  
Secondary Ion

Abstract. Over the last decades a suite of inorganic proxies based on foraminiferal calcite have been developed, of which some are now widely used for paleoenvironmental reconstructions. Studies of foraminiferal shell chemistry have largely focused on cations and oxyanions, while much less is known about the incorporation of anions. The halogens fluoride and chloride are conservative in the ocean, which makes them candidates for reconstructing paleoceanographic parameters. However, their potential as a paleoproxy has hardly been explored, and fundamental insight in their incorporation is required. Here we used nano-scale secondary ion mass spectrometry (NanoSIMS) to investigate, for the first time, the distribution of Cl and F within shell walls of four benthic species of foraminifera. In the rotaliid species Ammonia tepida and Amphistegina lessonii Cl and F were highly heterogeneous and correlated within the shell walls, forming bands that were co-located with the banded distribution of phosphorus. In the miliolid species Sorites marginalis and Archaias angulatus the distribution of Cl and F was much more homogeneous without discernible bands. In these species Cl and P were correlated, whereas no correlation was observed between Cl and F or between F and P. Additionally, their F content was about an order of magnitude higher than in the rotaliid species. The high variance in the Cl and F content in the studied foraminifera could not be attributed to environmental parameters. Based on these findings we suggest that in the rotaliid species Cl and F are predominately associated with organic linings. We further propose that in the miliolid species Cl may be incorporated as a solid solution of chlorapatite or associated with organic molecules in the calcite. The high F content together with the lack of correlation between Cl and F or P in the miliolid foraminifera suggests a fundamentally different incorporation mechanism. Overall, our data clearly show that the calcification pathway employed by the studied foraminifera governs the incorporation and distribution of Cl, F, P and other elements in their calcite shells.

A study of hydrogen diffusion in crystalline silicon by secondary-ion mass spectrometry

1989 ◽  
Vol 67 (4) ◽  
pp. 379-383 ◽  
Author(s):  
B. Y. Tong ◽  
X. W. Wu ◽  
G. R. Yang ◽  
S. K. Wong
Keyword(s):  
Mass Spectrometry ◽  
Diffusion Coefficient ◽  
Mass Spectroscopy ◽  
Hydrogen Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Crystalline Silicon ◽  
Nuclear Resonance ◽  
Secondary Ion Mass Spectroscopy ◽  
Flux Model ◽  
Secondary Ion

The diffusion coefficient of hydrogen in crystalline silicon, obtained from recent profiling experiments such as nuclear resonance retention and secondary-ion mass spectroscopy, is 3–9 orders of magnitude smaller than the previously accepted value measured by Van Wieringen and Warmoltz in 1956. Here we point out several items often overlooked in the analysis of profiling measurements. A limited flux model is proposed to explain the observed results. Predictions by the model are supported by further experiments.

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