scholarly journals Self- and Dopant Diffusion in Extrinsic Boron Doped Isotopically Controlled Silicon Multilayer Structures

2002 ◽  
Vol 719 ◽  
Author(s):  
Ian D. Sharp ◽  
Hartmut A. Bracht ◽  
Hughes H. Silvestri ◽  
Samuel P. Nicols ◽  
Jeffrey W. Beeman ◽  
...  
Keyword(s):  
Multilayer Structure ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Processes ◽  
Quantitative Description ◽  
Multilayer Structures ◽  
Dopant Diffusion ◽  
Enhanced Diffusion ◽  
Self Diffusion ◽  
Boron Doped ◽  
P Type

AbstractIsotopically controlled silicon multilayer structures were used to measure the enhancement of self- and dopant diffusion in extrinsic boron doped silicon. 30Si was used as a tracer through a multilayer structure of alternating natural Si and enriched 28Si layers. Low energy, high resolution secondary ion mass spectrometry (SIMS) allowed for simultaneous measurement of self- and dopant diffusion profiles of samples annealed at temperatures between 850°C and 1100°C. A specially designed ion-implanted amorphous Si surface layer was used as a dopant source to suppress excess defects in the multilayer structure, thereby eliminating transient enhanced diffusion (TED) behavior. Self- and dopant diffusion coefficients, diffusion mechanisms, and native defect charge states were determined from computer-aided modeling, based on differential equations describing the diffusion processes. We present a quantitative description of B diffusion enhanced self-diffusion in silicon and conclude that the diffusion of both B and Si is mainly mediated by neutral and singly positively charged self-interstitials under p-type doping. No significant contribution of vacancies to either B or Si diffusion is observed.

The Effect of Oxygen on The Electrical Activation and Diffusion of Ion-Implanted Boron

1997 ◽  
Vol 469 ◽  
Author(s):  
K. Kyllesbech Larsen ◽  
P. A. Stoik ◽  
V. Privitera ◽  
J. G. M. van Berkum ◽  
W. B. de Boer ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Secondary Ion Mass Spectrometry ◽  
Electrical Activation ◽  
Enhanced Diffusion ◽  
Boron Doped ◽  
Effect Of Oxygen ◽  
P Type ◽  
And Diffusion ◽  
Ion Implanted

ABSTRACTTransient enhanced diffusion (TED) and electrical activation (EA) of ion-implanted boron during rapid thermal annealing has been investigated using three types of boron doped p-type Si (100) substrates: (a) Cz 20 Ωcm, (b) 3 μm thick 20 Ωcm epitaxial Si layer (epi-layer) grown on a 20 Ωcm Cz substrate, and (c) 3 μm thick 20 Ωcm epi-layer grown on a 5 mΩcin Fz substrate. The level of oxygen is known to decrease from material type (a) to (c). The samples were implanted with 20 keV, 5×1013cm−2boron and subjected to rapid thermal annealing (RTA) at various temperatures and times. The EA and TED were studied using spreading resistance profiling (SRP) and secondary ion mass spectrometry (SIMS), respectively. Although the amount of TED is almost identical for the three substrates, the EA is found to be significantly higher in the epi-layers compared to Cz substrates. It is speculated that the trapping of vacancies by oxygen in the ion-damaged region leads to an increase in the interstitial supersaturation during annealing, which then results in enhanced boron clustering and reduced electrical activation in the peak of the implanted profile.

Diffusion Mechanisms in Sige Alloys

1999 ◽  
Vol 568 ◽  
Author(s):  
Arthur F.W. Willoughby ◽  
Janet M. Bonar ◽  
Andrew D.N. Paine
Keyword(s):  
Diffusion Processes ◽  
Dopant Diffusion ◽  
Elemental Silicon ◽  
Self Diffusion ◽  
Si Substrates ◽  
Marker Layer ◽  
Diffusion Mechanisms ◽  
Silicon And Germanium ◽  
Charged Defects

ABSTRACTInterest in diffusion processes in SiGe alloys arises from their potential in HBT's, HFET's, and optoelectronics devices, where migration over distances as small as a few nanometres can be significant. Successful modelling of these processes requires a much improved understanding of the mechanisms of self- and dopant diffusion in the alloy, although recent progress has been made. It is the purpose of this review to set this in the context of diffusion processes in elemental silicon and germanium, and to identify how this can help to elucidate behaviour in the alloy. Firstly, self diffusion processes are reviewed, from general agreement that self-diffusion in germanium is dominated by neutral and acceptor vacancies, to the position in silicon which is still uncertain. Germanium diffusion in silicon, however, appears to be via both vacancy and interstitial processes, and in the bulk alloy there is evidence for a change in dominant mechanism at around 35 percent germanium. Next, a review of dopant diffusion begins with Sb, which appears to diffuse in germanium by a mechanism similar to self-diffusion, and in silicon via monovacancies also, from marker layer evidence. In SiGe, the effects of composition and strain in epitaxial layers on Si substrates are also consistent with diffusion via vacancies, but questions still remain on the role of charged defects. The use of Sb to monitor vacancy effects such as grown-in defects by low temperature MBE, are discussed. Lastly, progress in assessing the role of vacancies and interstitials in the diffusion of boron is reviewed, which is dominated by interstitials in silicon-rich alloys, but appears to change to domination by vacancies at around 40 percent germanium, although studies in pure germanium are greatly needed.

Oxygen Gettering and Thermal Donor Formation at Post-Implantation Annealing of Hydrogen Implanted Czochralski Silicon

1997 ◽  
Vol 469 ◽  
Author(s):  
A. G. Ulyashin ◽  
Yu. A. Bumay ◽  
W. R. Fahrner ◽  
A. I. Ivanovo ◽  
R. Job ◽  
...  
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Hydrogen Ions ◽  
Enhanced Diffusion ◽  
Thermal Donor ◽  
Float Zone ◽  
Donor Formation ◽  
Effect Of Oxygen ◽  
P Type ◽  
Secondary Ion ◽  
Post Implantation

ABSTRACTThe effect of oxygen gettering by buried defect layers at post-implantation annealing of hydrogen implanted Czochralski (Cz) grown silicon has been investigated. Hydrogen ions were implanted with an energy of 180 keV and doses of 2.7.1016cm−2 into p-type Cz and for comparison into p-type float zone (Fz) Si. The samples were annealed at temperatures between 400 °C and 1200 °C in a forming gas ambient and examined by secondary ion mass spectrometry (SIMS) in order to measure the hydrogen and oxygen concentration profiles. Spreading resistance probe (SRP) measurements were used to obtain depth resolved profiles of the resistivity. The observed changes of the resistivity after post-implantation annealing of hydrogen implanted Cz and Fz Si can be explained by hydrogen enhanced thermal donor formation processes (oxygen or hydrogen related) and charges at the SiOx precipitates. The effective oxygen gettering in hydrogen implanted Cz silicon is attributed to hydrogen enhanced diffusion of oxygen to buried defect layers.

Self-Diffusion in Covalent Amorphous Solids – A Comparative Study Using Neutron Reflectometry and SIMS

2007 ◽  
Vol 263 ◽  
pp. 51-56 ◽  
Author(s):  
Harald Schmidt ◽  
Mukul Gupta ◽  
Udo Geckle ◽  
Michael Bruns
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Diffusion Length ◽  
Diffusion Processes ◽  
Amorphous Solid ◽  
Amorphous Solids ◽  
Neutron Reflectometry ◽  
Amorphous Silicon Nitride ◽  
Self Diffusion ◽  
Secondary Ion

The self-diffusion of nitrogen is studied in amorphous silicon nitride, which is a model system for a covalently bound amorphous solid with a low atomic mobility where reliable diffusion data are still lacking. Comparative experiments on Si14Nx/Si15Nx (x ≈ 1.33) isotope multilayers were carried out with secondary ion mass spectrometry (SIMS) and neutron reflectometry (NR), respectively. It was found that experiments with SIMS are not very well suited for the determination of diffusivities in a broad temperature range. The minimum diffusion length of about 5-10 nm detectable with this method is too large. At high temperatures (> 1200 °C) the amorphous solid crystallizes before any diffusion is measured and at low temperatures (< 1100 °C) the diffusivities are too low to be detected. In contrast, with neutron reflectometry diffusion lengths in the order of 1 nm and diffusivities down to 10-24 m2 s-1 were measured between 950 and 1250 °C. The potential of this method for the determination of ultra slow diffusion processes is discussed.

scholarly journals Dopant and Self-Diffusion in Extrinsic n-Type Silicon Isotopically Controlled Heterostructures

2002 ◽  
Vol 719 ◽  
Author(s):  
Hughes H. Silvestri ◽  
Ian D. Sharp ◽  
Hartmut A. Bracht ◽  
Sam P. Nicols ◽  
Jeff W. Beeman ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Multilayer Structure ◽  
Native Defect ◽  
Dopant Diffusion ◽  
Self Diffusion ◽  
Special Approach ◽  
Silicon Doped ◽  
Si Isotope ◽  
The Impact ◽  
Self Diffusion Coefficient

AbstractWe present experimental results of dopant- and self-diffusion in extrinsic silicon doped with As. Multilayers of isotopically controlled 28Si and natural silicon enable simultaneous analysis of 30Si diffusion into the 28Si enriched layers and dopant diffusion throughout the multilayer structure. In order to suppress transient enhanced self- and dopant diffusion caused by ion implantation, we adopted a special approach to dopant introduction. First, an amorphous 250-nm thick Si layer was deposited on top of the Si isotope heterostructure. Then the dopant ions were implanted to a depth such that all the radiation damage resided inside this amorphous cap layer. These samples were annealed for various times and temperatures to study the impact of As diffusion and doping on Si self-diffusion. The Si self-diffusion coefficient and the dopant diffusivity for various extrinsic n-type conditions were determined over a wide temperature range. We observed increased diffusivities that we attribute to the increase in the concentration of the native defect promoting the diffusion.

Elaboration of Porous Silicon Multilayer Using Resistive p-Type Si

2009 ◽  
Vol 609 ◽  
pp. 201-205
Author(s):  
O. Fellahi ◽  
T. Hadjersi ◽  
L. Guerbous
Keyword(s):  
Porous Silicon ◽  
Multilayer Structure ◽  
Multilayer Structures ◽  
Photoelectrochemical Etching ◽  
Anodization Time ◽  
Strong Luminescence ◽  
Current Densities ◽  
The Times ◽  
P Type ◽  
Crucial Parameter

Porous silicon is largely studied in the field of photonics because of its interesting optical properties. In this work we present an experimental study about the elaboration of a multilayer structure by photoelectrochemical etching. p-Si(100) with resistivity of 100 Ωcm is used in this work. Two different current densities were used namely 150 mA/cm2 and 10 mA/cm2. We found that the anodization time is a crucial parameter for the formation of multilayer structures. The times of 2 and 5 seconds appears as optimal times for the elaboration of multilayer structures with 16 layers. Finally, we have determined that these structures exhibit strong luminescence at 600 nm.

Aluminum and boron diffusion in 4H-SiC

2002 ◽  
Vol 742 ◽  
Author(s):  
M. K. Linnarsson ◽  
M. S. Janson ◽  
A. Schöner ◽  
B. G. Svensson
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Strong Dependence ◽  
Solubility Limit ◽  
Boron Diffusion ◽  
Enhanced Diffusion ◽  
Al Content ◽  
Diffusion Source ◽  
P Type ◽  
Secondary Ion

ABSTRACTA brief survey is given of some recent result of boron diffusion in low doped n-type (intrinsic) and p-type 4H-SiC. Aluminum diffusion and solubility limit in 4H-SiC are also discussed. Ion implantation of boron has been performed in epitaxial material to form a diffusion source but also epitaxial 4H-SiC structures, with heavily boron or aluminum doped layers prepared by vapor phase epitaxy have been studied. Heat treatments have been made at temperatures ranging from 1100 to 2050°C for 5 minutes up to 64 h. Secondary ion mass spectrometry has been utilized for analysis. For boron diffusion in acceptor doped 4H-SiC, 4×1019 Al atoms/cm3, an activation energy of 5.3 eV has been determined and a strong dependence on Al content for the diffusion coefficient is revealed. Transient enhanced diffusion of ion-implanted boron in intrinsic 4H-SiC samples is discussed. Solubility limits of ∼1×1020 Al/cm3 (1700°C) and <1×1020 B/cm3 (1900°C) have been deduced.

Effects of Concurrent Co or Ti Silicidation on Transient Diffusion and End-of-Range Damage in Phosphorus Implanted Silicon

1992 ◽  
Vol 262 ◽  
Author(s):  
J.W. Honeycutt ◽  
J. Ravi ◽  
G. A. Rozgonyi
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Complete Removal ◽  
Dislocation Loops ◽  
Enhanced Diffusion ◽  
Depth Profiles ◽  
Enhanced Dissolution ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Defect Behavior ◽  
Secondary Ion

ABSTRACTThe effects of Ti and Co silicidation on P+ ion implantation damage in Si have been investigated. After silicidation of unannealed 40 keV, 2×1015 cm-2 P+ implanted junctions by rapid thermal annealing at 900°C for 10–300 seconds, secondary ion mass spectrometry depth profiles of phosphorus in suicided and non-silicided junctions were compared. While non-silicided and TiSi2 suicided junctions exhibited equal amounts of transient enhanced diffusion behavior, the junction depths under COSi2 were significantly shallower. End-of-range interstitial dislocation loops in the same suicided and non-silicided junctions were studied by planview transmission electron microscopy. The loops were found to be stable after 900°C, 5 minute annealing in non-silicided material, and their formation was only slightly effected by TiSi2 or COSi2 silicidation. However, enhanced dissolution of the loops was observed under both TiSi2 and COSi2, with essentially complete removal of the defects under COSi2 after 5 minutes at 900°C. The observed diffusion and defect behavior strongly suggest that implantation damage induced excess interstitial concentrations are significantly reduced by the formation and presence of COSi2, and to a lesser extent by TiSi2. The observed time-dependent defect removal under the suicide films suggests that vacancy injection and/or interstitial absorption by the suicide film continues long after the suicide chemical reaction is complete.

scholarly journals Transport and Electromechanical Properties of Ca3TaGa3Si2O14 Piezoelectric Crystals at Extreme Temperatures

MRS Advances ◽  
2019 ◽  
Vol 4 (09) ◽  
pp. 515-521
Author(s):  
Yuriy Suhak ◽  
Ward L. Johnson ◽  
Andrei Sotnikov ◽  
Hagen Schmidt ◽  
Holger Fritze
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Tone Burst ◽  
Total Conductivity ◽  
Transport Mechanisms ◽  
Electromechanical Properties ◽  
Self Diffusion ◽  
Oxygen Ion ◽  
Piezoelectric Strain ◽  
Secondary Ion ◽  
Diffusion Profiles

ABSTRACTTransport mechanisms in structurally ordered piezoelectric Ca3TaGa3Si2O14 (CTGS) single crystals are studied in the temperature range of 1000-1300 °C by application of the isotope 18O as a tracer and subsequent analysis of diffusion profiles of this isotope using secondary ion mass spectrometry (SIMS). Determined oxygen self-diffusion coefficients enable calculation of oxygen ion contribution to the total conductivity, which is shown to be small. Since very low contributions of the cations have to be expected, the total conductivity must be dominated by electron transport. Ion and electron conductivities are governed by different mechanisms with activation energies (1.9±0.1) eV and (1.2±0.07) eV, respectively. Further, the electromechanical losses are studied as a function of temperature by means of impedance spectroscopy on samples with electrodes and a contactless tone-burst excitation technique. At temperatures above 650 °C the conductivity-related losses are dominant. Finally, the operation of CTGS resonators is demonstrated at cryogenic temperatures and materials piezoelectric strain constants are determined from 4.2 K to room temperature.

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