Onset of Extended Defect Formation and Enhanced Diffusion for Ultra-Low Energy Boron Implants

1999 ◽  
Vol 568 ◽  
Author(s):  
Jinning Liu ◽  
Kevin S. Jones ◽  
Daniel F. Downey ◽  
Sandeep Mehta
Keyword(s):  
Defect Formation ◽  
Low Energy ◽  
Dislocation Loops ◽  
Boron Diffusion ◽  
Extended Defect ◽  
Enhanced Diffusion ◽  
Annealing Conditions ◽  
Diffusion Enhancement ◽  
Spike Anneal ◽  
Low Thermal Budget

ABSTRACTTo meet the challenge of achieving ultra shallow p+/n source/drain extension junctions for 0.1 Oim node devices, ultra low energy boron implant and advanced annealing techniques have been explored. In this paper, we report the extended defect and boron diffusion behavior with various implant and annealing conditions. Boron implants were performed at energies from 0.25keV to lkeV and doses of 5 × 1014 cm−2 and 1 × 1015cm−2. Subsequent anneals were carried out in nitrogen ambient. The effect of energy, dose and oxide capping on extended defect formation and enhanced dopant diffusion was examined. It was observed that a thin screen oxide layer (35Å), grown prior to implantation, reduces the concentration of dopant in the Si by a significant amount as expected. This oxide also reduces the dislocation loops in the lattice and lowers diffusion enhancement of the dopant during annealing. The final junction depth can be optimized by using a low thermal budget spike anneal in a controlled oxygen ambient.

Monte Carlo simulation of Boron diffusion during low energy implantation and high temperature annealing

1997 ◽  
Vol 469 ◽  
Author(s):  
M.-J. Caturla ◽  
T. Diaz de la Rubia ◽  
J. Zhu ◽  
M. Johnson
Keyword(s):  
Monte Carlo ◽  
High Temperature ◽  
Kinetic Monte Carlo ◽  
Monte Carlo Model ◽  
Low Energy ◽  
High Temperature Annealing ◽  
Boron Diffusion ◽  
Enhanced Diffusion ◽  
Diffusion Enhancement ◽  
High Doses

ABSTRACTWe use a kinetic Monte Carlo model to simulate the implantation of low energy Boron in Silicon, from 0.5 to 1 keV, at high doses, 1015 ions/cm2. The damage produced by each ion is calculated using UT-Marlowe, based on a binary collision approximation. During implantation at room temperature,, silicon self-interstitials, vacancies and boron interstitials are allowed to migrate and interact. The diffusion kinetics of these defects and dopants has been obtained by ab initio calculations as well as Stillinger Weber molecular dynamics. Clustering of both self-interstitials, vacancies and boron atoms is included. We also model the diffusion of the implanted dopants after a high temperature annealing in order to understand the transient enhanced diffusion (TED) phenomenon. We observe two different stages of TED During the first stage vacancies are present in the lattice together with interstitials and the diffusion enhancement is small. The second stage starts after all the vacancies disappear and gives rise to most of the final TED.

Study of the Effects of a Two-Step Anneal on the End of Range Defects in Silicon

2002 ◽  
Vol 717 ◽  
Author(s):  
Renata A. Camillo-Castillo ◽  
Kevin. S. Jones ◽  
Mark E. Law ◽  
Leonard M. Rubin
Keyword(s):  
Defect Density ◽  
Low Energy ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Extended Defect ◽  
Enhanced Diffusion ◽  
Interstitial Concentration ◽  
Transmission Electron ◽  
Concentration Peak ◽  
Scale Down

AbstractTransient enhanced diffusion (TED) is a challenge that the semi-conductor industry has been faced with for more than two decades. Numerous investigations have been conducted to better understand the mechanisms that govern this phenomenon, so that scale down can be acheived. {311} type defects and dislocation loops are known interstitial sources that drive TED and dopants such as B utilize these interstitials to diffuse throughout the Si lattice. It has been reported that a two-step anneal on Ge preamorphized Si with ultra-low energy B implants has resulted in shallower junction depths. This study examines whether the pre-anneal step has a measurable effect on the end of range defects. Si wafers were preamorphized with Ge at 10, 12, 15, 20 and 30keV at a dose of 1x1015cm-2 and subsequently implanted with 1x1015cm-2 1keV B. Furnace anneals were performed at 450, 550, 650 and 750°C; the samples were then subjected to a spike RTA at 950°C. The implant damage was analyzed using Quantitative Transmission Electron Microscopy (QTEM). At the low energy Ge preamorphization, little damage is observed. However at the higher energies the microstructure is populated with extended defects. The defects evolve into elongated loops as the preanneal temperature increases. Both the extended defect density and the trapped interstitial concentration peak at a preanneal temperature of 550°C, suggesting that this may be an optimal condition for trapping interstitials.

Semi-Empirical Model for Boron Diffusion During Rapid Thermal Annealing of BF2 Implanted Silicon

1993 ◽  
Vol 303 ◽  
Author(s):  
Tzu-Hsin Huang ◽  
H. Kinoshita ◽  
D. L. Kwong
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Dislocation Loops ◽  
Boron Diffusion ◽  
Enhanced Diffusion ◽  
Defect Clusters ◽  
Annealing Conditions ◽  
Wide Range ◽  
Point Defect Clusters ◽  
Semi Empirical

ABSTRACTThe mechanism of the enhanced diffusion of boron during rapid thermal annealing (RTA) of BF2-implanted Si has been investigated, and a diffusion model is accordingly developed for a wide range of implant and annealing conditions. Simulation results are in excellent agreement with experiments for BF2 implant doses from 2×1013 to 5×1015cm−2, implant energies from 6 to 45 keV, and annealing temperatures from 950 to 1100°C. This model not only accounts for the transient enhanced diffusion due to the annealing of point-defect clusters and dislocation loops, but also for the retarded diffusion due to dopant precipitation. All the parameters used in this model are analytically determined.

The Effect of Fluorine Implantation on Boron Diffusion in Metastable Si0.86 Ge0.14

2004 ◽  
Vol 810 ◽  
Author(s):  
Huda A. W. A. El Mubarek ◽  
Yun Wang ◽  
Janet M. Bonar ◽  
Peter Hemment ◽  
Peter Ashburn
Keyword(s):  
Thermal Diffusion ◽  
Sige Layer ◽  
Dislocation Loops ◽  
Boron Diffusion ◽  
Rich Region ◽  
Implantation Energy ◽  
Enhanced Diffusion ◽  
Partial Relaxation ◽  
Transient Enhanced Diffusion ◽  
Marker Layer

ABSTRACTThis paper investigates the effect of varying F+ implantation energy on boron thermal diffusion and boron transient enhanced diffusion (TED) in metastable Si0.86Ge0.14 by characterising the diffusion of a boron marker layer in samples with and without P+ and F+ implants. The effect of two F+ implantation energies (185keV and 42keV) was studied at two anneal temperatures 950°C and 1025°C. In samples implanted with P+ & 185keV F+, the fluorine suppresses boron transient enhanced diffusion completely at 950°C and suppresses thermal diffusion by 25% at 1025°C. In samples implanted with P+ & 42keV F+, the fluorine does not reduce boron transient enhanced diffusion at 950°C. This result is explained by the location of the boron marker layer in the vacancy-rich region of the fluorine damage profile for the 185keV implant but in the interstitial-rich region for the 42keV implant. Isolated dislocation loops are seen in the SiGe layer for the 185keV implant. We postulate that these loops are due to the partial relaxation of the metastable Si0.86Ge0.14 layer.

The Influence of Amorphizing Implants on Boron Diffusion in Silicon

1997 ◽  
Vol 469 ◽  
Author(s):  
H. S. Chao ◽  
P. B. Griffin ◽  
J. D. Plummer
Keyword(s):  
Point Defects ◽  
Field Enhancement ◽  
Enhancement Effect ◽  
Dislocation Loops ◽  
Boron Diffusion ◽  
Electric Field Enhancement ◽  
Diffusion Behavior ◽  
Enhanced Diffusion ◽  
Pile Up ◽  
Experimental Structure

ABSTRACTThe transient enhanced diffusion behavior of B after ion implantation above the amorphization threshold is investigated. The experimental structure uses a layer of epitaxially grown Si, uniformly doped with B to act as a diffusion monitor. Wafers using this structure are implanted with amorphizing doses of Si, As, or P and annealed for various times at various temperatures. The experimental results show that upon annealing after Si implantation, there is a large amount of B pile-up that occurs at the amorphous/crystalline (A/C) interface while B is depleted from the region just beyond the A/C interface. This pile-up/depletion phenomenon can be attributed to the dislocation loops that form at the A/C interface. These loops act as sinks for interstitial point defects. There is also B pile-up/depletion behavior for As and P implants as well. However, this behavior may be explained by an electric field enhancement effect. While dislocation loops are known to form at the A/C interface for all of the investigated implant conditions, it appears that while they are necessary to simulate for Si amorphizing implants, they may not be necessary to simulate for As and P amorphizing implants.

Atomistic simulations of extrinsic defects evolution and transient enhanced diffusion in silicon

2001 ◽  
Vol 669 ◽  
Author(s):  
A. Claverie ◽  
B. Colombeau ◽  
F. Cristiano ◽  
A. Altibelli ◽  
C. Bonafos
Keyword(s):  
Ostwald Ripening ◽  
Physical Modelling ◽  
Defect Layer ◽  
Low Energy ◽  
Atomistic Simulations ◽  
Correct Prediction ◽  
Dislocation Loops ◽  
Enhanced Diffusion ◽  
Loss Term ◽  
Extrinsic Defects

ABSTRACTWe have implemented an atomistic simulation of the Ostwald ripening of extrinsic defects (clusters, {113}'s and dislocation loops) which occurs during annealing of ion implanted silicon. Our model describes the concomitant time evolution of the defects and of the supersaturation of Si interstitial atoms in the region. It accounts for the capture and emission of these interstitials to and from extrinsic defects (defined by their formation energy) of sizes up to thousands of atoms and includes a loss term due to the interstitial flux to the surface. This model reproduces well the dissolution of {113} defects in Si implanted wafers. We have subsequently studied the characteristics of TED in the case of B implantation at low and ultra low energy. In such cases, the distance between the defect layer and the surface plays a crucial role in determining the TED decay time. The simulations show that defect dissolution occurs earlier and for smaller sizes in the ultra-low energy regime. Under such conditions, TED is mostly characterized by its “pulse” component which takes place at the very beginning of the anneal, probably during the ramping up. In summary, we have shown that the physical modelling of the formation and of the growth of extrinsic defects leads to a correct prediction of the “source term” of Si interstitials and at the origin of TED.

Effects of Interstitial Clustering on Transient Enhanced Diffusion of Boron in Silicon

1996 ◽  
Vol 439 ◽  
Author(s):  
S. Solmi ◽  
S. Valmorri
Keyword(s):  
Diffusion Mechanism ◽  
Boron Diffusion ◽  
Experimental Conditions ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Good Account ◽  
Diffusion Enhancement ◽  
Heavily Doped ◽  
Kinetics Of ◽  
New Phase

AbstractA simulation model for Boron diffusion which takes into account the aggregation of the excess interstitials in clusters, and subsequently, the dissolution of these defects, is proposed. The interstitial supersaturation and generation rate are determined according to the classical theory of nucleation and growth of particles, in analogy with the precipitation of a new phase in heavily doped silicon. The clusters are considered as precipitates formed by interstitial Si atoms. The B diffusion is modelled on the basis of the dopant-interstitial pair diffusion mechanism. The clusters dissolution during annealing maintains nearly constant, for a long period, the interstitial supersaturation and the related enhancement of the boron diffusion. This gives a good account of the diffusion results over a large range of experimental conditions. Furthermore, this approach describes most of the behavior of the transient enhanced diffusion (TED), like the temperature dependence of the level of the B diffusion enhancement, the dependence of the duration of the phenomenon on implanted dose, and the scarce dependence on the damage distribution in depth. The results of the simulations are compared with experimental data on the kinetics of interstitial cluster dissolution and of B TED.

Modeling of Damage Enhanced Diffusion of Implanted Boron in Silicon

1990 ◽  
Vol 201 ◽  
Author(s):  
V. C. Lo ◽  
S. P. Wong ◽  
Y. W. Lam
Keyword(s):  
High Dose ◽  
Boron Diffusion ◽  
Furnace Annealing ◽  
Enhanced Diffusion ◽  
Annealing Conditions ◽  
Boron Implantation ◽  
Dominant Point ◽  
Local Relaxation ◽  
And Diffusion ◽  
Defect Species

AbstractModeling of the damage enhanced diffusion (DED) behaviors of implanted boron in silicon of Powell’s experiment [1] has been performed. In his experiment, Powell showed that the diffusion of implanted boron in silicon was dependent on implantation dosage as well as on the annealing conditions. For low dose boron implantation, the extent of boron diffusion after 15 second RTP is less than that of furnace annealing at 900°C for 30 minutes. But the reverse is true for the high dose case, and a two-step annealing leads to least and minimal diffusion. In this work, implantation induced excess self-interstitials which generate mobile boron atoms at the intersititial sites are considered the dominant point defect species responsible for the DED. Both the local relaxation and diffusion of these excess self-interstitials are considered. The features of the DED reported by Powell are successfully reproduced and explained.

Fundamental Modeling of Transient Enhanced Diffusion through Extended Defect Evolution

1997 ◽  
Vol 469 ◽  
Author(s):  
A. H. Gencer ◽  
S. Chakravarthi ◽  
I. Clejan ◽  
S. T. Dunham
Keyword(s):  
Point Defect ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Extended Defect ◽  
Enhanced Diffusion ◽  
Fundamental Model ◽  
Transient Enhanced Diffusion ◽  
Defect Evolution

Prediction of transient enhanced diffusion (TED) requires modeling of extended defects of many types, such as {311} defects, dislocation loops, boron-interstitial clusters, arsenic precipitates, etc. These extended defects not only form individually, but they also interact with each other through changes in point defect and solute concentrations. We have developed a fundamental model which can account for the behavior of a broad range of extended defects, as well as their interactions with each other. We have successfully applied and parameterized our model to a range of systems and conditions, some of which are presented in this paper.

Defect Evolution from Low Energy, Amorphizing, Germanium Implants on Silicon

2001 ◽  
Vol 669 ◽  
Author(s):  
Andres F. Gutierrez ◽  
Kevin S. Jones ◽  
Daniel F. Downey
Keyword(s):  
Time Window ◽  
Low Energy ◽  
Dislocation Loops ◽  
Medium Energy ◽  
Evolutionary Pathway ◽  
Plan View ◽  
Enhanced Diffusion ◽  
Conventional Furnace ◽  
Transmission Electron ◽  
Defect Evolution

ABSTRACTPlan-view transmission electron microscopy (PTEM) was used to characterize defect evolution upon annealing of low-to-medium energy, 5-30 keV, germanium implants into silicon. The implant dose was 1 × 1015 ions/cm2, sufficient for surface amorphization. Annealing of the samples was done at 750 °C in nitrogen ambient by both rapid thermal annealing (RTA) and conventional furnace, and the time was varied from 10 seconds to 360 minutes. Results indicate that as the energy drops from 30 keV to 5 keV, an alternate path of excess interstitials evolution may exist. For higher implant energies, the interstitials evolve from clusters to {311}'s to loops as has been previously reported. However, as the energy drops to 5 keV, the interstitials evolve from clusters to small, unstable dislocation loops which dissolve and disappear within a narrow time window, with no {311}'s forming. These results imply there is an alternate evolutionary pathway for {311} dissolution during transient enhanced diffusion (TED) for these ultra-low energy implants.

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