Kinetic Model of Thermal Donor Evolution

1997 ◽  
Vol 469 ◽  
Author(s):  
K. F. Kelton ◽  
R. Falster
Keyword(s):  
Interstitial Oxygen ◽  
Oxygen Loss ◽  
Free Oxygen ◽  
Czochralski Silicon ◽  
Thermal Donor ◽  
Cluster Evolution ◽  
Oxygen Precipitation ◽  
High Diffusion Rate ◽  
Normal Diffusion ◽  
Small Clusters

ABSTRACTKinetic aspects of thermal donor (TD) formation in Czochralski silicon are shown to be consistent with the evolution of small oxygen clusters, as described within the classical theory of nucleation. Predictions for TD generation and interstitial oxygen loss are presented. Favorable agreement with experimental data requires that the rate constants describing cluster evolution be increased over those expected for a oliffusion-limited flux based on a normal diffusion coefficient for oxygen in silicon. This may signal an anomalously high diffusion rate for temperatures less than 500°C, as has been suggested by others. However, it may instead signal an enhanced concentration of free oxygen near clusters smaller than the critical size for nucleation. This is expected when the interfacial attachment rates become comparable with the rates at which oxygen atoms arrive in the vicinity of the sub-critical clusters. The link between thermal donor generation and oxygen precipitation processes demonstrated here provides a consistent framework for better understanding and controlling oxygen precipitation in silicon. Further, the kinetic TD generation and oxygen loss data provide a new window into the dynamical processes for small clusters, which underlie all nucleation phenomena.

First Principles Calculation for Point Defect Behavior, Oxygen Precipitation and Cu Gettering in Czochralski Silicon

2005 ◽  
Vol 108-109 ◽  
pp. 365-372 ◽  
Author(s):  
Koji Sueoka ◽  
S. Shiba ◽  
S. Fukutani
Keyword(s):  
Crystal Growth ◽  
Point Defect ◽  
First Principles ◽  
First Principles Calculation ◽  
Interstitial Oxygen ◽  
Defect Engineering ◽  
Czochralski Silicon ◽  
Oxygen Precipitation ◽  
Initial Stage ◽  
P Type

Theoretical consideration for technologically important phenomena in defect engineering of Czochralski silicon was performed with first principles calculation. (i) Point defect behaviour during crystal growth, (ii) enhanced oxygen precipitation in p/p+ epitaxial wafers, and (iii) Cu gettering by impurities are main topics in this work. Following results are obtained. (i) Interstitial Si I is dominant in p type Si while vacancy V is dominant in n type Si during crystal growth when dopant concentration is higher than about 1x1019atoms/cm3. (ii) In initial stage of oxygen precipitation including a few interstitial oxygen (O) atoms, BOn complex is more stable than On complex. The diffusion barrier of O atom in p+ Si is reduced to about 2.2eV compared with the barrier of about 2.5eV in intrinsic Si. (iii) In substitutional B, Sb, As, P and C atoms, only B atom can be an effective gettering center for Cu.

Influence of Grown-in Hydrogen on Thermal Donor Formation and Oxygen Precipitation in Czochralski Silicon Crystals

1994 ◽  
Vol 33 (Part 1, No. 10) ◽  
pp. 5577-5584 ◽  
Author(s):  
Akito Hara ◽  
Masaaki Koizuka ◽  
Masaki Aoki ◽  
Tetsuo Fukuda ◽  
Hiroshi Yamada-Kaneta ◽  
...  
Keyword(s):  
Czochralski Silicon ◽  
Thermal Donor ◽  
Silicon Crystals ◽  
Oxygen Precipitation ◽  
Donor Formation

Internal Gettering in Czochralski Silicon

1984 ◽  
Vol 36 ◽  
Author(s):  
Robert A. Craven
Keyword(s):  
Simple Model ◽  
Integrated Circuit ◽  
Czochralski Silicon ◽  
Thermal Donor ◽  
Oxygen Precipitation ◽  
Integrated Circuit Fabrication ◽  
Circuit Fabrication

ABSTRACTA review of the use of oxygen precipitation for the purposes of internal gettering in silicon is given. The review considers current ideas about oxygen precipitation mechanisms and the relationships between different precipitate morphologies. Two different paths for oxygen precipitation are considered, the first path being 450C thermal donor - coesite defects and the second being <100> oriented platelets. A summary of the uses of oxygen precipitation gettering in integrated circuit fabrication and a simple model for optimization of internal gettering follows the precipitation discussion.

On the Kinetics of Oxygen Clustering and Thermal Donor Formation in Czochralski Silicon

1985 ◽  
Vol 59 ◽  
Author(s):  
T. Y. Tan ◽  
R. Kleinhenz ◽  
C. P. Schneider
Keyword(s):  
Oxygen Concentration ◽  
Kinetic Models ◽  
The Other ◽  
Concentration Data ◽  
Czochralski Silicon ◽  
Thermal Donor ◽  
Donor Formation ◽  
Small Clusters ◽  
Kinetics Of ◽  
Overall Kinetics

ABSTRACTWe report the results of an experiment of annealing Czochralski silicon at 450°C for up to 500 hrs. Concentrations of oxygen atoms (Ci) and thermal donors (TD) have both been monitored. Analyses of the oxygen concentration data yielded the apparent interpretation that the overall kinetics is dominated by the formation of small clusters (dimers and trimers). This cannot account for TD formation, since they are supposed to be larger clusters. On the other hand, analyses of existing TD kinetic models did not yield calculated Ci values to satisfactorily account for the present Ci data. We believe that a satisfactory TD model is not yet available.

Measurements of Enhanced Oxygen Diffusion in Silicon During Thermal Donor Formation: New Evidence for Possible Mechanisms

1989 ◽  
Vol 163 ◽  
Author(s):  
A.R. Brown ◽  
R. Murray ◽  
R.C. Newman ◽  
J.H. Tucker
Keyword(s):  
Oxygen Diffusion ◽  
Diffusion Rate ◽  
Oxygen Loss ◽  
Enhanced Diffusion ◽  
Czochralski Silicon ◽  
Thermal Donor ◽  
Annealed Material ◽  
Primary Mechanism ◽  
Donor Formation ◽  
New Evidence

AbstractCzochralski silicon has been heated in a H-plasma at temperatures in the range 300-450°C, and compared with furnace annealed material. Plasma treatments produce enhanced rates of oxygen diffusion jumps, loss of oxygen from solution and formation of thermal donor centres. The available evidence indicates that atomic hydrogen catalyses the enhancements via the oxygen diffusion rate. Donor concentrations greater than 1017cm-3 have been observed in samples heated in a plasma at 350°C. Doubts have been raised about dimer formation being the primary mechanism for oxygen loss in furnace anneals at 350°C, but invoking enhanced diffusion leads to a conflict with stress dichroism data.

Oxygen Aggregation Phenomena in Silicon

1987 ◽  
Vol 104 ◽  
Author(s):  
Ronald C. Newman
Keyword(s):  
Activation Energy ◽  
Critical Analysis ◽  
Diffusion Rate ◽  
Apparent Increase ◽  
Enhanced Diffusion ◽  
Czochralski Silicon ◽  
Oxygen Precipitation ◽  
Normal Diffusion ◽  
Kinetics Of ◽  
Aggregation Phenomena

ABSTRACTOxygen precipitation in Czochralski silicon heated in the range 400–1050°C is reviewed. For T≥525° C, Si02 particles form at the normal diffusion rate and there is generation of self-interstitials. At the lower temperatures, the existence of the interfacial energy causes an apparent increase in the solid solubility as the agglomerates become very small: at 525° C they contain only an estimated 20–50 atoms. A critical analysis s then presented of possible oxygen aggregation reactions at even lower temperatures when thermal donors are generated. It is not yet possible to reconcile the kinetics of these two processes, even if self-interstitials and/or vacancy reactions are included. There is no evidence for enhanced diffusion of isolated oxygen atoms except as a transient process occurring during the relaxation of stress-induced dichroism. Oxygen aggregation at 450 ° C appears to be limited by the formation of dimers with an activation energy of 2.5eV, while thermal donors form with an activation energy of 1.7eV.

Oxygen Precipitation in Silicon: Numerical Models

1985 ◽  
Vol 59 ◽  
Author(s):  
J. P. Lavine ◽  
G. A. Hawkins ◽  
C. N. Anagnostopoulos ◽  
L. Rivaud
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Numerical Models ◽  
Local Concentration ◽  
Interstitial Oxygen ◽  
Czochralski Silicon ◽  
Oxygen Precipitation ◽  
Precipitate Growth ◽  
Evolution Of Precipitates ◽  
Precipitate Density

ABSTRACTWe present a numerical model that simulates the evolution of precipitates and the diffusion of interstitial oxygen in Czochralski silicon. The growth and/or dissolution of each precipitate and the local concentration of interstitial oxygen with which the precipitates interact are followed as a function of time. We treat realistic densities of discrete, interacting precipitates and determine how the precipitate density influences the extent of the precipitation. The model also treats oxygen outdiffusion and the formation of precipitate-free or denuded zones. We apply the model to previous experimental data on the time dependence of precipitate growth and to the development of denuded zones during intrinsic gettering.

Structure of Thermally-Induced Microdefects in Czochralski Silicon

1983 ◽  
Vol 31 ◽  
Author(s):  
F. A. Ponce ◽  
S. Hahn
Keyword(s):  
Quasi Equilibrium ◽  
Interstitial Oxygen ◽  
Thermally Induced ◽  
Czochralski Silicon ◽  
Oxygen Precipitation ◽  
Transmission Electron ◽  
Long Time ◽  
History Of ◽  
Silicon Materials ◽  
Oxygen Precipitates

ABSTRACTThe process of oxygen precipitation in Czochralski silicon materials has been studied using high resolution transmission electron microscopy. The resulting structure depends strongly on the thermal history of the material. The initial stages of precipitation involve the formation of clusters exhibiting strain fields which are coherent and isotropic at intermediate temperatures (∼7000°C). Incoherent defects are formed when the interstitial oxygen precipitates into substitutional sites in the silicon lattice. For long-time anneals, the quasi-equilibrium defect structure ranges from needle-like coesite (450–600°C), silica platelets (600–1000°C) to polyhedral silica precipitates (900–1200°C).

Oxygen loss during thermal donor formation in Czochralski silicon: New insights into oxygen diffusion mechanisms

1995 ◽  
Vol 77 (4) ◽  
pp. 1427-1442 ◽  
Author(s):  
S. A. McQuaid ◽  
M. J. Binns ◽  
C. A. Londos ◽  
J. H. Tucker ◽  
A. R. Brown ◽  
...  
Keyword(s):  
Oxygen Diffusion ◽  
Oxygen Loss ◽  
Czochralski Silicon ◽  
Thermal Donor ◽  
Donor Formation ◽  
Diffusion Mechanisms

The Effects of Carbon on Czochralski Silicon Used for Dynamic Random Access Memory Production

1985 ◽  
Vol 59 ◽  
Author(s):  
R. A. Craven ◽  
W. E. Bailey ◽  
J. W. Moody ◽  
R. J. Falster ◽  
L. W. Shive
Keyword(s):  
Defect Density ◽  
Random Access ◽  
Relative Yield ◽  
Peak Performance ◽  
Interstitial Oxygen ◽  
Active Device ◽  
Recombination Lifetime ◽  
Czochralski Silicon ◽  
Oxygen Precipitation ◽  
Heterogeneous Processes

ABSTRACTCzochralski silicon with constant controlled oxygen level of 15+/-0.5 ppma (ASTM F121–80) and varying carbon content intentionally doped at five different levels from 0.1 ppma to 4.1 ppma (ASTM F123–81) was used to fabricate 16K dynamic random access memories, MOS test capacitors with guard rings, and pn junctions. The results of the experiment have been analyzed for relative yield to functional and refresh characteristics, MOS generation and bulk recombination lifetime, pn junction leakage, and both surface and bulk defect densities. Peak performance of the silicon did not occur at the lowest carbon level, but was dominated by the oxygen precipitate defect density and depth of the denuded zone near the active device regions. The results of the capacitor measurements, the DRAM yield measurements, the junction leakage measurements and the bulk and surface lifetime measurements are self-consistent and emphasize the need for control of the oxygen precipitation whether it is nucleated by carbon or other homogeneous and heterogeneous processes. There is no evidence that carbon has any impact on the device performance other than its impact on the precipitation kinetics of the interstitial oxygen.

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