Reactions of point defects and dopant atoms in silicon

1992 ◽  
Vol 69 (1) ◽  
pp. 116-119 ◽  
Author(s):  
N. E. B. Cowern ◽  
G. F. A. van de Walle ◽  
P. C. Zalm ◽  
D. J. Oostra
Keyword(s):  
Point Defects ◽  
Dopant Atoms

Pts-Oi Complex Formation in Platinum Diffused Silicon

2005 ◽  
Vol 864 ◽  
Author(s):  
Wilfried Vervisch ◽  
Laurent Ventura ◽  
Bernard Pichaud ◽  
Gérard Ducreux ◽  
André Lhorte
Keyword(s):  
Thermal Treatment ◽  
Complex Formation ◽  
Cooling Rate ◽  
Point Defects ◽  
Diffusion Processes ◽  
Silicon Wafers ◽  
Doping Behaviour ◽  
Simulation Results ◽  
Dopant Atoms ◽  
P Type

AbstractWhen platinum is diffused at temperatures higher than 900°C in Cz or FZ low doped n-type silicon samples, which are then cooled slowly in the range [1-10]°C/min, a p-type doping leading to the formation of a pn junction can be observed by spreading resistance measurement. The lower the cooling rate, the deeper the junction is. This junction disappears after a second thermal treatment finishing with a quenching step. A platinum related complex formation is considered to explain this reversible doping behaviour. Different possible interactions between platinum and other impurities such as dopant atoms, intrinsic point defects, and common residual impurities (C, Oi, transition metallic atoms) are studied here. Experimental results from Pt diffusion processes in different qualities of silicon wafers, and simulation results, lead to the conclusion that the platinum related p-type doping effect is due to the formation of a Pts-Oi complex.

Point defects, dopant atoms, and compensation effects in CdSe and CdS cleavage surfaces

1999 ◽  
Vol 343-344 ◽  
pp. 537-540
Author(s):  
B. Siemens ◽  
C. Domke ◽  
Ph. Ebert ◽  
K. Urban
Keyword(s):  
Point Defects ◽  
Dopant Atoms

Structure And Composition Of Grain Boundaries In SrTiO3

1999 ◽  
Vol 5 (S2) ◽  
pp. 94-95
Author(s):  
O. Kienzle ◽  
F. Ernst ◽  
Manfred Rühle
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Point Defects ◽  
Coincidence Site Lattice ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
Boundary Structure ◽  
Dopant Atoms ◽  
Charged Point ◽  
Atomistic Structure

The electrical properties of SrTiO3 (strontium titanate) ceramics are strongly influenced or even dictated by grain boundary segregation of charged point defects, such as dopant atoms, impurities, vacancies, or self-interstitials. The atomistic structure of the grain boundaries, their energy, and the segregation of point defects mutually depend on each other. Grain boundary segregation of charged point defects induces the formation of space charge layers in the adjoining crystals. In order to investigate the relation between grain boundary structure and composition, grain boundaries in Fedoped SrTiO3 bicrystals and in SrTiO3 ceramics were studied by HRTEM and by AEM with subnanometer resolution.Quantitative HRTEM served to investigate the atomistic structure of Σ=3, (111) grain boundaries in Fe-doped SrTiO3 bicrystals with a doping level of Fe/Ti= 0.04at% (Fig. 1). Analysis of the translation state revealed that the Σ=3, (111) grain boundary has an excess volume: normal to the boundary plane, the spacing between the two crystals exceeds what one would expect from a coincidence site lattice model by (0.06 ±0.01 )nm.

Point Defects and Diffusion in Semiconductors

MRS Bulletin ◽  
1991 ◽  
Vol 16 (11) ◽  
pp. 42-46 ◽  
Author(s):  
Ulrich M. Gösele ◽  
Teh Y. Tan
Keyword(s):  
Point Defects ◽  
Integrated Circuit ◽  
Diffusion Processes ◽  
Semiconductor Industry ◽  
Surface Oxidation ◽  
Optoelectronic Device ◽  
Intrinsic Point Defects ◽  
Impurity Atoms ◽  
Circuit Fabrication ◽  
Dopant Atoms

Semiconductor devices generally contain n- and p-doped regions. Doping is accomplished by incorporating certain impurity atoms that are substitutionally dissolved on lattice sites of the semiconductor crystal. In defect terminology, dopant atoms constitute extrinsic point defects. In this sense, the whole semiconductor industry is based on controlled introduction of specific point defects. This article addresses intrinsic point defects, ones that come from the native crystal. These defects govern the diffusion processes of dopants in semiconductors. Diffusion is the most basic process associated with the introduction of dopants into semiconductors. Since silicon and gallium arsenide are the most widely used semiconductors for microelectronic and optoelectronic device applications, this article will concentrate on these two materials and comment only briefly on other semiconductors.A main technological driving force for dealing with intrinsic point defects stems from the necessity to simulate dopant diffusion processes accurately. Intrinsic point defects also play a role in critical integrated circuit fabrication processes such as ion-implantation or surface oxidation. In these processes, as well as during crystal growth, intrinsic point defects may agglomerate and negatively impact the performance of electronic or photovoltaic devices. If properly controlled, point defects and their agglomerates may also be used to accomplish positive goals such as enhancing device performance or processing yield.

Low-Temperature Diffusion of Dopants in Silicon

1989 ◽  
Vol 163 ◽  
Author(s):  
P. Fahey ◽  
M. Wittmer
Keyword(s):  
Low Temperature ◽  
Transition Metal ◽  
Experimental Evidence ◽  
Point Defects ◽  
Low Temperatures ◽  
Surprising Result ◽  
Temperature Diffusion ◽  
Doped Silicon ◽  
Diffusion Enhancement ◽  
Dopant Atoms

AbstractIt has been reported that diffusion of substitutional dopant atoms in silicon occurs during the formation of transition-metal suicides at temperatures below 300°C. By observing the diffusion enhancements of buried marker layers of Sb-, Ga-, Ge-, and B-doped silicon layers, we provide solid experimental evidence that the diffusion enhancement induced by Pd2Si formation at low temperatures is due to point defects generated by the suicide reactions. Diffusion enhancement is observed at temperatures as low as 200°C. We have found the surprising result that diffusion is asymmetric: diffusion occurs preferentially towards the suiciding interface.

Properties of Point-Defects in Si for Process Modeling

1995 ◽  
Vol 389 ◽  
Author(s):  
H.-J. Gossmann ◽  
C. S. Rafferty ◽  
P. A. Stolk ◽  
D. J. Eaglesham ◽  
G. H. Gilmer ◽  
...  
Keyword(s):  
Point Defects ◽  
Quantitative Information ◽  
Recombination Coefficient ◽  
Native Point Defects ◽  
Front End ◽  
Atomistic Calculations ◽  
Equilibrium Concentrations ◽  
Dopant Atoms ◽  
Physical Phenomena ◽  
Impurity Profiles

ABSTRACTThe development of future Si device technologies will rely extensively on modeling, requiring truly predictive tools. Here we focus on the front-end processes, during which ion-implantation and annealing create 3-D impurity profiles that determine crucial electrical device parameters. The final configuration is the result of a complex interaction of dopant atoms with Si self-interstitials and vacancies, which themselves interact with each other as well as with the implantation-induced damage and interfaces. Predictive modeling requires for all these processes a solid understanding of the physical phenomena as well as accurate quantitative information. Si self-interstitials and vacancies are not observable directly in an experiment, but only via their interactions with some other physical quantity of the sample. We review our work employing dopant atoms in δ-doping superlattices (δ-DSL) that yield directly the time averaged depth profiles of Si native point defects during a particular processing sequence. This approach is uniquely suited for giving insights into the interplay of point defects in Si, providing crosschecks for atomistic calculations as well as parameters for process simulators. We describe experiments to extract interstitial and vacancy parameters and discuss the influence of intrinsic and extrinsic interstitial traps, as well as of the annealing environment, on the native point defect population. The latter allows to place certain bounds on the interstitial vacancy recombination coefficient as well as the ratio of interstitial and vacancy equilibrium concentrations.

Point Defects Migration and Agglomeration in Si at Room Temperature: The Role of Surface and Impurity Content

1997 ◽  
Vol 469 ◽  
Author(s):  
V. Privitera ◽  
S. Coffa ◽  
K. Kyllesbech Larsen ◽  
S. Libertino ◽  
G. Mannino ◽  
...  
Keyword(s):  
Point Defects ◽  
Room Temperature ◽  
Deep Level ◽  
Ion Beam ◽  
Impurity Content ◽  
Sample Surface ◽  
Defect Migration ◽  
Transient Spectroscopy ◽  
Dopant Atoms

ABSTRACTOur recent work on the room temperature migration and trapping phenomena of self-interstitials and vacancies in crystalline Si is reviewed. Spreading resistance profiling and deep level transient spectroscopy measurements were used to monitor the interaction of ion beam generated defects with dopant atoms, intrinsic impurities (i.e. O and C), pre-existing defect marker layers and sample surface. We have found that both interstitials and vacancies undergo fast long range migration which is interrupted by trapping at impurities and by recombination at defects or at the surface. Effective defect migration lengths as large as 5 μm at room temperature have been observed in highly pure, defect free epitaxial Si samples. A lower limit of 1×10−10 cm2/sec for the room temperature diffusivity of self-interstitials has been determined. Furthermore, by monitoring the migration and interaction processes of point defects injected through a mask, we have established that surface acts as an effective sink for the migrating Si self interstitials.

Microstructural Evolution in Reduced TiO2

1981 ◽  
Vol 39 ◽  
pp. 74-75
Author(s):  
W. T. Donlon ◽  
S. Shinozaki ◽  
E. M. Logothetis ◽  
W. Kaizer
Keyword(s):  
Microstructural Evolution ◽  
Point Defects ◽  
Extended Defects ◽  
Small Deviations ◽  
Controlled Atmospheres ◽  
Limited Solubility ◽  
Thin Foils ◽  
Heat Treated ◽  
Porous Polycrystalline ◽  
Crystallographic Shear

Since point defects have a limited solubility in the rutile (TiO2) lattice, small deviations from stoichiometry are known to produce crystallographic shear (CS) planes which accomodate local variations in composition. The material used in this study was porous polycrystalline TiO2 (60% dense), in the form of 3mm. diameter disks, 1mm thick. Samples were mechanically polished, ion-milled by conventional techniques, and initially examined with the use of a Siemens EM102. The electron transparent thin foils were then heat-treated under controlled atmospheres of CO/CO2 and H2 and reexamined in the same manner.The “as-received” material contained mostly TiO2 grains (∼5μm diameter) which had no extended defects. Several grains however, aid exhibit a structure similar to micro-twinned grains observed in reduced rutile. Lattice fringe images (Fig. 1) of these grains reveal that the adjoining layers are not simply twin related variants of a single TinO2n-1 compound. Rather these layers (100 - 250 Å wide) are alternately comprised of stoichiometric TiO2 (rutile) and reduced TiO2 in the form of Ti8O15, with the Ti8O15 layers on either side of the TiO2 being twin related.

Simulated Dark-Field Electron Micrographs of Point Defects and Organometallics

1975 ◽  
Vol 33 ◽  
pp. 200-201
Author(s):  
William Krakow
Keyword(s):  
Electron Micrographs ◽  
Point Defects ◽  
Structure Determination ◽  
Atomic Structure ◽  
Image Interpretation ◽  
Dark Field ◽  
Field Electron ◽  
Dark Field Microscopy ◽  
Dark Field Electron

Tilted beam dark-field microscopy has been applied to atomic structure determination in perfect crystals, several synthesized molecules with heavy atcm markers and in the study of displaced atoms in crystals. Interpretation of this information in terms of atom positions and atom correlations is not straightforward. Therefore, calculated dark-field images can be an invaluable aid in image interpretation.

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