Defects Induced by Helium Implantation: Impact on Boron Diffusivity

2005 ◽  
Vol 864 ◽  
Author(s):  
F. Cayrel ◽  
D. Alquier ◽  
C. Dubois ◽  
R. Jerisian
Keyword(s):  
Defect Density ◽  
Defect Layer ◽  
High Dose ◽  
Boron Diffusion ◽  
Enhanced Diffusion ◽  
Helium Implantation ◽  
Buried Layer ◽  
Boron Diffusivity ◽  
Induced Defects ◽  
Metallic Impurities

AbstractHigh dose helium implantation followed by a suitable thermal treatment induces defects such as cavities and dislocations. Gettering efficiency of this technique for metallic impurities has been widely proved. Nevertheless, dopants, as well as point defects, interact with this defect layer. Due to the presence of vacancy type defects after helium implantation, boron diffusion can be largely influenced by such a buried layer. In this paper, we study the influence of helium induced defects on boron diffusion. The boron diffusion in presence of these defects has been analyzed as a function of different parameters such as distance between boron profile and defect layer and defect density. Our results demonstrate that the major impact known as boron enhanced diffusion can be partially or completely suppressed depending on parameters of experiments. Moreover, these results clarify the interaction of boron with extended He-induced defects.

Analysis and Suppression of Process-Induced Defects in Memory Devices.

2000 ◽  
Vol 610 ◽  
Author(s):  
R. Annunziata ◽  
R. Bottini ◽  
P. Colpani ◽  
C. Cremonesi ◽  
G. Ghidini ◽  
...  
Keyword(s):  
Point Defect ◽  
Defect Density ◽  
Amorphous Layer ◽  
High Dose ◽  
Thermal Treatments ◽  
Memory Devices ◽  
Layer Width ◽  
Implantation Energy ◽  
Induced Defects ◽  
The Impact

AbstractIn this paper we show that dopant decoration of process-induced defects is responsible for a failure mechanism of memory devices. From the electrical point-of-view, the defect-related failure consists in a source-to-drain resistive path formed by junction piping. This mechanism is made active by the very close spacing which is typical of present device structures. A device-like test structure is used for defect detection. This structure proves to be a very effective tool for studying the impact of various process steps on defect generation, in that it allowes statistical data about the formation of these defects to be collected. TEM analyses are extensively used for studying the evolution of end-of-range defects during subsequent thermal treatments and for measuring the amorphous layer width under various implantation conditions.The role of high dose implantations in the generation of this sort of defects is discussed. Even if the amorphous layer is completely recovered by a suitable recristallization annealing, residual defects grow and become dopant-decorated during post-implantation thermal treatments. Defect density is increased by oxidizing treatments. In this case point defect injection is active both in enhancing dopant diffusion and in growing defects.Defect formation is suppressed if the amorphous layer is made very shallow (≤ 50 nm) by suitable choices of the screen oxide and of the implantation energy. A binary collision code is used in order to estimate the dependence on energy of the self-interstitial excess outside the amorphous region. The results of these calculations indicate that defect suppression can be tentatively explained by point defect annihilation at the silicon surface.

Effect of Nitrogen Implants on Boron Transient Enhanced Diffusion

2000 ◽  
Vol 610 ◽  
Author(s):  
Omer Dokumaci ◽  
Paul Ronsheim ◽  
Suri Hegde ◽  
Dureseti Chidambarrao ◽  
Lahir Shaik-Adam ◽  
...  
Keyword(s):  
Low Temperature ◽  
Boron Diffusion ◽  
High Nitrogen ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
High Boron ◽  
Buried Layer ◽  
Higher Doses ◽  
Low Nitrogen ◽  
Temperature Furnace

AbstractThe effect of nitrogen implants on boron transient enhanced diffusion was studied for nitrogen-only, boron-only, and boron plus nitrogen implants. A boron buried layer was used as a detector for interstitial supersaturation in the samples. Boron dose ranged from 1×1014 to 1×1015 cm−2 and N2+ dose from 5×1013 and 5×1014 cm−2. The energies were chosen such that the location of the nitrogen and boron peaks matched. After the implants, RTA and low temperature furnace anneals were carried out. The diffusivity enhancements were extracted from the buried layer profiles by simulation. Nitrogen-only implants were found to cause significant enhanced diffusion on the buried boron layer. For lower doses, the enhancement of the nitrogen implant is about half as that of boron whereas the enhancements are equal at higher doses. Nitrogen coimplant with boron increases the transient enhanced diffusion of boron at low boron doses, which implies that nitrogen does not act as a strong sink for excess interstitials unlike carbon. At high boron doses, nitrogen co-implant does not significantly change boron diffusion. Sheet resistance measurements indicate that low nitrogen doses do not affect the activation of boron whereas high nitrogen doses either reduce the activation of boron or the mobility of the holes.

Impact of Hydrogen Implantation on Helium Implantation Induced Defects

2005 ◽  
Vol 108-109 ◽  
pp. 309-314 ◽  
Author(s):  
G. Gaudin ◽  
Frédéric Cayrel ◽  
Corrado Bongiorno ◽  
Robert Jérisian ◽  
Vito Raineri ◽  
...  
Keyword(s):  
Cavity Growth ◽  
High Dose ◽  
Defect Band ◽  
Hydrogen Addition ◽  
Recent Developments ◽  
Hydrogen Implantation ◽  
Helium Implantation ◽  
Silicon Based ◽  
Induced Defects ◽  
The Impact

Silicon-based power device performances are largely affected by metal contamination occurring during device manufacturing. Among the usual gettering techniques, recent developments were done on high dose helium implantation. Even though the gettering efficiency of this technique has been demonstrated in device application, the required doses are still extremely high for an industrial application. Recently, it has been shown that the use of H/He co-implantation limits the total requested doses [1]. In this paper, co-implantation of H/He, which has been already used to reduce the dose in the smart-cut® process is explored. The goal of this work is to decrease efficiently the implanted dose maintaining an efficient metallic gettering without degrading the Si surface. The impact of H implantation on He implantation induced defects is carefully studied. The TEM observations have evidenced that hydrogen addition drastically modified the defect band structure and promotes the cavity growth.. Additionally, we demonstrate that an efficient gettering can be obtained.

Defects Induced by Helium Implantation: Interaction with Boron and Phosphorus

2002 ◽  
Vol 719 ◽  
Author(s):  
F. Cayrel ◽  
D. Alquier ◽  
F. Roqueta ◽  
L. Ventura ◽  
C. Dubois ◽  
...  
Keyword(s):  
Annealing Temperature ◽  
Isothermal Annealing ◽  
Defect Layer ◽  
High Dose ◽  
Dopant Distribution ◽  
Dopant Segregation ◽  
Trapping Mechanism ◽  
Helium Implantation ◽  
Suitable Technique ◽  
Shed Light

AbstractHigh dose He implantation, followed by a thermal annealing, is a suitable technique for metal gettering. Nevertheless, a strong interaction between the dopants and the defect layer has been evidenced. This can largely influence the dopant distribution. In order to study this interaction, p and n-type samples uniformly doped were implanted with helium (40 keV, 5×1016 He+.cm-2) and furnace annealed for various times and temperatures. In this paper, we shed light on the evolution of the dopant segregation. Using isochronal treatment, we found a large dependence of the dopant gettering phenomenon upon annealing temperature. Moreover, stability of the gettered fraction is observed for isothermal annealing. This study permits also to investigate the origin of the trapping mechanism involved for both boron and phosphorus.

Effect of Fluorine on the Diffusion of Boron in Amorphous Silicon

2002 ◽  
Vol 717 ◽  
Author(s):  
J. M. Jacques ◽  
L. S. Robertson ◽  
K. S. Jones ◽  
Joe Bennett
Keyword(s):  
Amorphous Silicon ◽  
Boron Concentration ◽  
Solid Phase ◽  
Amorphous Layer ◽  
Boron Diffusion ◽  
Enhanced Diffusion ◽  
Diffusion Characteristics ◽  
Junction Formation ◽  
Amorphous Surface ◽  
Boron Diffusivity

AbstractFluorine and boron co-implantation within amorphous silicon has been studied in order to meet the process challenges regarding p+ ultra-shallow junction formation. Previous experiments have shown that fluorine can reduce boron TED (Transient Enhanced Diffusion), enhance boron solubility and reduce sheet resistance. In this study, boron diffusion characteristics prior to solid phase epitaxial regrowth (SPER) of the amorphous layer in the presence of fluorine are addressed. Samples were pre-amorphized with Si+ at a dose of 1x1015 ions/cm2 and energy of 70 keV, leading to a deep continuous amorphous surface of approximately 1500 Å. After pre-amorphization, B+ was implanted at a dose of 1x1015 ions/cm2 and energy of 500 eV, while F+ was implanted at a dose of 2x1015 ions/cm2 and energies ranging from 3 keV to 9 keV. Subsequent furnace anneals for the F+ implant energy of 6 keV were conducted at 550°C, for times ranging from 5 minutes to 260 minutes. During annealing, the boron in samples co-implanted with fluorine exhibited significant enhanced diffusion within amorphous silicon. After recrystallization, the boron diffusivity was dramatically reduced. Boron in samples with no fluorine did not diffuse during SPER. Prior to annealing, SIMS profiles demonstrated that boron concentration tails broadened with increasing fluorine implant energy. Enhanced dopant motion in as-implanted samples is presumably attributed to implant knock-on or recoil effects.

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.

Transient Enhanced Diffusion of Dopants in Preamorphised Si Layers

1996 ◽  
Vol 438 ◽  
Author(s):  
A. Claverie ◽  
C. Bonafos ◽  
M. Omri ◽  
B. De Mauduit ◽  
G. Ben Assayag ◽  
...  
Keyword(s):  
Ostwald Ripening ◽  
Dislocation Loops ◽  
Boron Diffusion ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Interstitial Atoms ◽  
Extrinsic Dislocation ◽  
The Mean ◽  
Boron Diffusivity ◽  
Shed Light

AbstractTransient Enhanced Diffusion (TED) of dopants in Si is the consequence of the evolution, upon annealing, of a large supersaturation of Si self-interstitial atoms left after ion bombardment. In the case of amorphizing implants, this supersaturation is located just beneath the c/a interface and evolves through the nucleation and growth of End-Of-Range (EOR) defects.For this reason, we discuss here the relation between TED and EOR defects. Modelling of the behavior of these defects upon annealing allows one to understand why and how they affect dopant diffusion. This is possible through the development of the Ostwald ripening theory applied to extrinsic dislocation loops. This theory is shown to be readily able to quantitatively describe the evolution of the defect population (density, size) upon annealing and gives access to the variations of the mean supersaturation of Si self-interstitial atoms between the loops and responsible for TED. This initial supersaturation is, before annealing, at least 5 decades larger than the equilibrium value and exponentially decays with time upon annealing with activation energies that are the same than the ones observed for TED. It is shown that this time decay is precisely at the origin of the transient enhancement of boron diffusivity through the interstitial component of boron diffusion. Side experiments shed light on the effect of the proximity of a free surface on the thermal behavior of EOR defects and allow us to quantitatively describe the space and time evolutions of boron diffusivity upon annealing of preamorphised Si layers.

Post-Oxidation Enhanced Diffusion of Low-Energy Implanted Boron in Ultra-Shallow P+/N Junctions Formation

2000 ◽  
Vol 610 ◽  
Author(s):  
D. Lenoble ◽  
A. Halimaoui ◽  
A. Grouillet
Keyword(s):  
Experimental Data ◽  
Simple Model ◽  
Reflection Coefficient ◽  
Mirror Effect ◽  
Low Energy ◽  
Boron Diffusion ◽  
Enhanced Diffusion ◽  
Boron Diffusivity ◽  
First Time

AbstractIn this paper, we report for the first time the effect of sacrificial oxide (sacox) on the boron diffusion in ultra-shallow P+/N junctions. It is shown that the boron diffusivity is enhanced when low energy implantations are performed through sacrificial oxide. The various experimental data lead to conclude that the Post-Oxidation Enhanced Diffusion (POED) is due to a « mirror effect » seen by the Si interstitials incoming into the sacox layer. POED occurs even for sacox as thin as 1.5 nm. From a simple model, the reflection coefficient is estimated to be about 100 % for a 2.5 nm-thick sacox.

Effects of Arsenic Deactivation on Arsenic-Implant Induced Enhanced Diffusion in Silicon

1995 ◽  
Vol 396 ◽  
Author(s):  
O. Dokumaci ◽  
M.E. Law ◽  
V. Krishnamoorthy ◽  
K.S. Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Dose ◽  
Enhanced Diffusion ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Type V ◽  
Boron Diffusivity

AbstractThe enhanced diffusion of boron due to high dose arsenic implantation into silicon is studied as a function of arsenic dose. The behavior of both the type-V and end-of-range loops is investigated by transmission electron microscopy (TEM). The role of arsenic deactivation induced interstitials and type-V loops on enhanced diffusion is assessed. Reduction of the boron diffusivity is observed with increasing arsenic dose at three different temperatures. The possible explanations for this reduction are discussed.

Quantitative Measurement of Reduction of Boron Diffusion by Substitutional Carbon Incorporation

1998 ◽  
Vol 527 ◽  
Author(s):  
M. S. Carroll ◽  
L. D. Lanzerotti ◽  
J. C. Sturm
Keyword(s):  
Quantitative Measurement ◽  
Device Modeling ◽  
Electrical Characteristics ◽  
Boron Diffusion ◽  
Carbon Incorporation ◽  
Combined Process ◽  
Enhanced Diffusion ◽  
Interstitial Concentration ◽  
Transient Enhanced Diffusion ◽  
Boron Diffusivity

ABSTRACTRecently, the suppression of boron diffusion due to both thermal and transient enhanced diffusion (TED) has been demonstrated through the incorporation of 0.5% substitutional carbon in the base of Si/SiGe/Si heterojunction transistor's (HBT)[1,2]. Because the devices are sensitive to diffusion on a scale less than that we can detect with SIMS, in this paper combined process and device modeling (TMA TSUPREM4 and MEDICI) are used to relate observed electrical characteristics (collector saturation currents and Early voltages) of the HBT's to boron diffusion, with a sensitivity of 20-30Å. Boron diffusivity in the SiGeC base is ~8 times slower than that of the boron diffusivity in the SiGe base without implant damage (no TED). In the case of ion implant damage in an overlying layer to cause TED the excess interstitial concentration due to ion implant damage is reduced by approximately 99% through incorporation of 0.5% substitutional carbon in the HBT SiGe bases. This demonstrates that carbon incorporation acts as an effective sink for interstitials.

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