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.

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.

Vacancy Species Produced by Rapid Thermal Annealing of Silicon Wafers

2015 ◽  
Vol 242 ◽  
pp. 135-140 ◽  
Author(s):  
Vladimir V. Voronkov ◽  
Robert Falster
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Silicon Wafers ◽  
Density Profiles ◽  
Cooling Stage ◽  
Czochralski Silicon ◽  
Self Diffusion ◽  
Oxygen Precipitation ◽  
Oxide Precipitate ◽  
Precipitate Density

Rapid thermal annealing (RTA) of Czochralski silicon wafers at around 1260°C installs a depth profile of some vacancy species. Subsequent oxygen precipitation in such wafers is vacancy-assisted. The data on RTA-installed vacancy profiles - and the corresponding precipitate density profiles - suggest that there is a slow-diffusing vacancy species (Vs) along with two fast-diffusing species: a Watkins vacancy (Vw) manifested in irradiation experiments and fast vacancy (Vf) responsible for the high-T vacancy contribution into self-diffusion. The Vs species are lost during cooling stage of RTA, and the loss seems to occur by conversion of Vs into Vf followed by a quick out-diffusion of Vf. A model based on this scenario provides a good fit to the reported profiles of oxide precipitate density in RTA wafers for different values of TRTA and different cooling rates.

Study of the Mechanisms of Oxygen Precipitation in RTA Annealed Cz-Si Wafers

2009 ◽  
Vol 156-158 ◽  
pp. 279-282
Author(s):  
V.G. Litovchenko ◽  
I.P. Lisovskyy ◽  
M. Voitovych ◽  
Andrey V. Sarikov ◽  
S.O. Zlobin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Infrared Spectroscopy ◽  
Kinetic Model ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Defect Structure ◽  
Oxide Phase ◽  
Interstitial Oxygen ◽  
Single Crystalline ◽  
Oxygen Precipitation

In this paper, the influence of the rapid thermal annealing of single crystalline Cz-Si wafers on the evolution of the concentration of interstitial oxygen as well as oxygen in precipitated oxide phase was investigated by infrared spectroscopy. The wafers were preliminary furnace annealed to create the precipitate seeds. The concentration of interstitial oxygen was shows to decrease considerably as a result of annealing during up to 40 min together with the growth of the concentration of precipitated oxygen. This effect depended on the purity and defect structure of initial wafers. The kinetic model was developed to account for the observed effects based on the modification of the solubility level for interstitial oxygen induced by defects as well as its diffusivity. Obtained results of simulation agree well with the experimental data.

Numerical study of flow pattern around lateral intake in a curved channel

2019 ◽  
Vol 30 (11) ◽  
pp. 1950083 ◽  
Author(s):  
Hossien Montaseri ◽  
Hossein Asiaei ◽  
Abdolhossein Baghlani ◽  
Pourya Omidvar
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Flow Pattern ◽  
Numerical Study ◽  
Numerical Models ◽  
Three Dimensional ◽  
Curved Channel ◽  
Channel Bend ◽  
Outer Bank ◽  
Center Region

This paper deals with numerical study of flow field in a channel bend in presence of a lateral intake using three-dimensional numerical model SSIIM2. The effects of bend on the structure of the flow around the intake are investigated and compared with the experimental data. The tests are carried out in a U-shaped channel bend with a lateral intake. The intake is located at the outer bank of an 180∘ bend at position 115∘ with 45∘ diversion angle and the experimental data can be used to calibrate and validate numerical models. The results show that both the center-region and outer-bank cross-stream circulations are observed in the experiments while only the former is captured by the numerical model due to the limitations of the turbulence model. In the curved channel after the intake, both experimental and numerical results show another type of bi-cellular circulations in which clockwise center-region circulations and counterclockwise circulations near the inner bank and the free surface (inner-bank circulations) are captured. The study shows that the numerical model very satisfactorily predicts streamlines, velocity field and flow pattern in the channel and in vicinity of the intake. Investigation of flow pattern around lateral intake in channel bends shows that contrary to the case of flow diversion in straight channels, the width of the dividing stream surface near water surface level is greater than that of near bed level. Finally, the effects of position and diversion angle of the lateral intake, discharge ratio and upstream Froude number on the flow pattern are investigated.

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.

Early stages of oxygen precipitation in si: morphology and structure

1988 ◽  
Vol 46 ◽  
pp. 478-479
Author(s):  
W. Bergholz ◽  
J. L. Hutchison
Keyword(s):  
High Pressure ◽  
Controversial Issues ◽  
Interstitial Oxygen ◽  
Oxygen Precipitation ◽  
Oxygen Precipitate ◽  
Initial Stage ◽  
Vlsi Technology ◽  
Precipitate Growth ◽  
Morphology And Structure ◽  
Pressure Phase

Intrinsic gettering in Si - VLSI technology depends on a controlled initial stage of oxygen precipitation and is characterized by a complicated interaction of growth-induced microdefects, self interstitial (SiI) generation and strain caused by SiO2 precipitate growth and secondary defects, table 1. We address the controversial issues of the identity of ribbon-like defects (RLDs) and of the nature of oxygen precipitate nuclei.RLDs were initially identified by HRTEM as coesite, a high pressure phase of SiO2. Recently, both Bourret and Reiche et al have interpreted the RLDs as hexagonal Si, or agglomerates of Si. We wish to make the point that the evidence against coesite is, as yet, not conclusive, and present circumstantial evidence in favour of coesite: (1) The loss of interstitial oxygen correlates with the density of RLDs (Fig. 1) at 450 - 485°C.

Combined Experimental and Numerical Study for Multiple Microchannel Heat Transfer System

2010 ◽  
Author(s):  
Jingru Zhang ◽  
Yogesh Jaluria ◽  
Tiantian Zhang ◽  
Li Jia
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Steady State ◽  
Numerical Model ◽  
Initial Conditions ◽  
Numerical Study ◽  
Numerical Models ◽  
Three Dimensional ◽  
Variation Versus ◽  
Heat Transfer System

Multiple microchannel heat sinks for potential use for electronic chip cooling are studied experimentally and numerically to characterize their thermal performance. The numerical simulation is driven by experimental data, which are obtained concurrently, to obtain realistic, accurate and validated numerical models. The ultimate goal is to design and optimize thermal systems. The experimental setup was established and liquid flow in the multiple microchannels was studied under different flow rates and heat influx. The temperature variation versus time was recorded by thermocouples, from which the time needed to reach steady state was determined. Temperature variations under steady state conditions were compared with three-dimensional steady state numerical simulation for the same boundary and initial conditions. The experimental data served as input parameters for the validation of the numerical model. In case of discrepancy, the numerical model was improved. A fairly good agreement between the experimental and simulation results was obtained. The numerical model also served to provide input that could be employed to improve and modify the experimental arrangement.

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 Precipitation in Silicon: Monte Carlo and Deterministic Studies

1988 ◽  
Vol 141 ◽  
Author(s):  
James P. Lavine ◽  
Russell J. Taras ◽  
Gilbert A. Hawkins
Keyword(s):  
Monte Carlo ◽  
Oxygen Concentration ◽  
Three Dimensional ◽  
Nucleation Site ◽  
Interstitial Oxygen ◽  
Oxygen Precipitation ◽  
Nucleation Sites ◽  
Precipitate Growth ◽  
Oxygen Precipitates ◽  
Oxygen Atoms

AbstractInterstitial oxygen precipitates in silicon during thermal treatment. The amount precipitated increases in an S-shaped fashion as a function of increasing initial interstitial oxygen concentration. A likely hypothesis for this behavior is that the number of nucleation sites that develop into precipitates (successful sites) varies with the initial interstitial oxygen concentration as well as with the precipitation rate at each site. In this paper, a deterministic precipitate growth model is first used to show that a fit to the present data requires the precipitate density to increase by more than a factor of 10 when the oxygen concentration goes from 24 to 40 ppma.Three-dimensional Monte Carlo calculations are then used to show how the nucleation site survival probability depends on the initial number of oxygen atoms at the site and the oxygen concentration. The program treats oxygen diffusion, growth at nucleation sites by the addition of oxygen atoms, and loss at nucleation sites by the escape of oxygen atoms.

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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