Device Parametric Shift Mechanism Caused by Boron Halo Redistribution Resulting from Dose Rate Dependence of SDE Implant

2005 ◽  
Vol 864 ◽  
Author(s):  
Ukyo Jeong ◽  
Jinning Liu ◽  
Baonian Guo ◽  
Kyuha Shim ◽  
Sandeep Mehta
Keyword(s):  
Surface Region ◽  
Amorphous Region ◽  
Amorphous Layer ◽  
High Dose ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Near Surface ◽  
Enhanced Diffusion ◽  
Dose Rates ◽  
Pile Up

AbstractChange in dopant diffusion was observed for Arsenic source drain extension (SDE) implants when they were performed at various dose rates. The high dose SDE implant amorphizes the surface of the silicon substrate and the thickness of the amorphous layer is strongly influenced by the rate of dopant bombardment. It is well known that the ion implantation process introduces excess interstitials. While the amorphous region is completely re-grown into single crystal during subsequent anneal without leaving behind extended defects, interstitials that are injected beyond the amorphous layer lead to formation of {311} defects or dislocation loops in the end of range region. During thermal processing, these extended defects dissolve, release interstitials, which in turn lead to transient enhanced diffusion of underlying Boron halo dopant. Dopant depth profiles measured by SIMS revealed different amount of Boron pile-up in the near surface region, corresponding to different SDE implant dose rates. In CMOS devices, this surface pile-up would correlate with a Boron pile-up in the channel region that would lead to a shift in transistor characteristics. Through this investigation, we were able to explain the mechanism causing device characteristics shift resulted from SDE implant with the same dose and energy but different dose rates.

Effect of Extended Defects on the Enhanced Diffusion of Phosphorus Implanted Silicon

1999 ◽  
Vol 568 ◽  
Author(s):  
P. H. Keys ◽  
J. H. Li ◽  
E. Heitman ◽  
P. A. Packan ◽  
M. E. Law ◽  
...  
Keyword(s):  
Species Interactions ◽  
Secondary Ion Mass Spectrometry ◽  
Ion Beam ◽  
Effective Diffusion ◽  
Chemical Species ◽  
High Dose ◽  
Extended Defects ◽  
Near Surface ◽  
Enhanced Diffusion ◽  
Marker Layer

ABSTRACTExtended defects resulting from ion implantation are believed to act in some cases as a driving force behind transient enhanced diffusion (TED). We use secondary ion mass spectrometry (SIMS) to study the diffusion enhancements of an underlying boron doped spike after creating implant damage in the near surface region. Diffusion enhancements are compared for silicon implants and phosphorus implants to distinguish between factors related to chemical species interactions versus those related to ion beam damage. Transmission electron microscopy (TEM) is used to investigate the existence and dissolution of extended defects. {311} extended defects are clearly visible in self-implanted samples but absent in phosphorus doped samples. The extended defects resulting from phosphorus implantation are small (20Å to 60Å diameter) “dot” defects barely resolvable by conventional TEM. methods. Despite the marked differences in defect morphology, diffusion enhancements in the boron marker layer are observable for both species. Results comparing the TED of a buried marker layer after P+ and Si+ show a larger overall effective diffusion length results after high dose (1x1014 cm−2) phosphorus implants. Visible defects in phosphorus implanted silicon are not the only source of TED, suggesting the existence of sub-microscopic phosphorus interstitial clusters (PIC). This provides important insight into the affect of phosphorus on TED.

Influence of the Temperature of Implantation on the Morphology of Defects in MeV Implanted GaAs.

1989 ◽  
Vol 147 ◽  
Author(s):  
G. Braunstein ◽  
Samuel Chen ◽  
S.-Tong Lee ◽  
G. Rajeswaran.
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Point Defects ◽  
Room Temperature ◽  
Surface Region ◽  
Amorphous Region ◽  
Liquid Nitrogen Temperature ◽  
Dislocation Loops ◽  
Near Surface ◽  
Epitaxial Regrowth

AbstractWe have studied the influence of the temperature of implantation on the morphology of the defects created during 1-MeV implantation of Si into GaAs, using RBS-channeling and TEM. The annealing behavior of the disorder has also been investigated.Implantation at liquid-nitrogen temperature results in the amorphization of the implanted sample for doses of 2×1014 cm−2 and larger. Subsequent rapid thermal annealing at 900°C for 10 seconds leads to partial epitaxial regrowth of the amorphous layer. Depending on the implantation dose, the regrowth can proceed from both the front and back ends of the amorphous region or only from the deep end of the implanted zone. Nucleation and growth of a polycrystalline phase occurs concurrently, limiting the extent of the epitaxial regrowth. After implantation at room temperature and above, two distinct types of residual defects are observed or inferred: point defect complexes and dislocation loops. Most of the point defects disappear after rapid thermal annealing at temperatures ≥ 700°C. The effect of annealing on the dislocation loops depends on the distance from the surface of the sample. Those in the near surface region disappear upon rapid thermal annealing at 700°C, whereas the loops located deeper in the sample grow in size and begin to anneal out only at temperatures in excess of 900°C. Implantation at temperatures of 200 - 300°C results in a large reduction in the number of residual point defects. Subsequent annealing at 900°C leads to a nearly defect-free surface region and, underneath that, a buried band of partial dislocation loops similar to those observed in the samples implanted at room temperature and subsequently annealed.

Germanium Implantation into Silicon: An Alternate Pre-Amorphization/Rapid Thermal Annealing Procedure for Shallow Junction Technology

1983 ◽  
Vol 23 ◽  
Author(s):  
D.K. Sadana ◽  
E. Myers ◽  
J. Liu ◽  
T. Finstad ◽  
G.A. Rozgonyi
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Surface Region ◽  
Amorphous Layer ◽  
High Dose ◽  
Dislocation Loops ◽  
Cross Sectional ◽  
Defect Clusters ◽  
Ion Damage ◽  
Free Material

ABSTRACTGermanium implantation into Si was conducted to pre-amorphize the-si surface layer prior to a shallow/high dose (42 keV, 2 × 1015 cm−2) BF2 implant. Cross-sectional transmission electron microscopy showed that rapid thermal annealing (RTA) of the amorphous layer (without BF2 ) leaves defect-free material in the implanted region. Only a discrete layer of small (∼300Å) dislocation loops due to straggling ion damage was found to be present at a depth corresponding to the amorphous/crystalline interface. RTA of the amorphous layer with the BF2 creatpd a high density of uniformly. distributed fine defect clusters (∼50Å) in the surface region (0–500Å) in addition to the straggling ion damage. Boron and F profiles obtained by secondary ion mass spectrometry from the unannealed and rapid thermally annealed samples showed the presence of high concentrations of these impurities in the surface region where the fine defect clusters were observed. A comparison of the RTA behavior of the pre-amorphized surface layers (with or without BF2 ) produced by Ge and self-implantation is presented.

scholarly journals Enhanced Diffusion of Dopants in Vacancy Supersaturation Produced by MeV Implantation

1997 ◽  
Vol 469 ◽  
Author(s):  
V. C. Venezia ◽  
T. E. Haynes ◽  
A. Agarwal ◽  
H. -J. Gossmann ◽  
D. J. Eaglesham
Keyword(s):  
Surface Layer ◽  
Surface Region ◽  
Silicon On Insulator ◽  
Rich Region ◽  
Near Surface ◽  
Enhanced Diffusion ◽  
Float Zone ◽  
Transient Enhanced Diffusion

ABSTRACTThe diffusion of Sb and B markers has been studied in vacancy supersaturations produced by MeV Si implantation in float zone (FZ) silicon and bonded etch-back silicon-on-insulator (BESOI) substrates. MeV Si implantation produces a vacancy supersaturated near-surface region and an interstitial-rich region at the projected ion range. Transient enhanced diffusion (TED) of Sb in the near surface layer was observed as a result of a 2 MeV Si+, 1×1016/cm2, implant. A 4× larger TED of Sb was observed in BESOI than in FZ silicon, demonstrating that the vacancy supersaturation persists longer in BESOI than in FZ. B markers in samples with MeV Si implant showed a factor of 10× smaller diffusion relative to markers without the MeV Si+ implant. This data demonstrates that a 2 MeV Si+ implant injects vacancies into the near surface region.

Defects Introduced by Plasma Processing of Silicon

1992 ◽  
Vol 262 ◽  
Author(s):  
J. L. Benton
Keyword(s):  
Bulk Material ◽  
Surface Region ◽  
Surface Damage ◽  
Near Surface ◽  
Enhanced Diffusion ◽  
Interstitial Defect ◽  
Comprehensive Picture ◽  
Reaction Region ◽  
Defect Reactions ◽  
P Type

ABSTRACTThe electrical and optical properties of defects introduced by Reactive Ion Etching (RIE) in the near surface region of Si after dry etching with various gases and plasma conditions is studied with spreading Resistance (SR), photoluminescence (PL), and capacitance-voltage profiling (C-V). Plasma etching in chlorine and fluorine based gases produce donors at the surface in both n-type and p-type, Czochralski and float-zone silicon. Isochronal annealing reveals the presence of two distinct regions of dopant compensation. The surface damage region is confined to 1000 Å and survives heat treatment at 400°C, while the defect reaction region extends ≥ 1 μm in depth and recovers by 250°C. A comprehensive picture of the interstitial defect reactions in RIE silicon is completed. The interstitial defects, Ci and Bi, created in the ion damaged near surface region, undergo recombination enhanced diffusion caused by the presence of ultraviolet light in the plasma, resulting in the long range diffusion into the Si bulk. Subsequently, the interstitial atoms are trapped by the background impurities forming the defect pairs, CiOi, CSCi, or BiOi, which are observed experimentally. The depth of the diffusion-limited trapping and the probability of forming specific pairs depends on the relative concentrations of the reactants, oxygen, carbon or boron, present in the bulk material.

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.

On the Energetics of Extrinsic Defects in Si and their Role in Nonequilibrium Dopant Diffusion

2000 ◽  
Vol 610 ◽  
Author(s):  
Alain Claverie ◽  
Filadelfo Cristiano ◽  
Benjamin Colombeau ◽  
Nicholas Cowern
Keyword(s):  
Formation Energy ◽  
Ostwald Ripening ◽  
High Dose ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Dynamical Equilibrium ◽  
Defect Interactions ◽  
Small Clusters ◽  
Dose Levels ◽  
Extrinsic Defects

AbstractIn this paper, we discuss the mechanisms by which small clusters evolve through “magic” sizes into {113} defects and then, at sufficiently high dose levels, transform into dislocation loops of two types. This ripening process is mediated by the interchange of free Si(int)s between different extended defects, leading to a decrease of their formation energy. The calculation of the supersaturation of free Si-interstitials in dynamical equilibrium with these defects shows a hierarchy of levels of nonequilibrium diffusion, ranging from supersaturations S of about 106 in the presence of small clusters, through 103 in the presence of {113} defects, to S in the range 100 down to 1 as loops are formed, evolve and finally evaporate. A detailed analysis of defect energetics has been carried out and it is shown that Ostwald ripening is the key concept for understanding and modelling defect interactions during TED of dopants in silicon.

Using Ion Beams to Modify Nanocrystalline Composites: Co Nanoparticles in Sapphire

2001 ◽  
Vol 703 ◽  
Author(s):  
A. Meldrum ◽  
K.S. Beaty ◽  
M. Lam ◽  
C.W. White ◽  
R.A. Zuhr ◽  
...  
Keyword(s):  
Surface Region ◽  
Amorphous Layer ◽  
Ion Beams ◽  
Near Surface ◽  
Nanocrystalline Composites ◽  
Transmission Electron ◽  
Co Nanoparticles ◽  
20 Nm ◽  
And Control ◽  
Single Crystal Sapphire

ABSTRACTIon implantation and thermal processing were used to create a layer of Co nanoclusters embedded in the near-surface region of single-crystal sapphire. The Co nanoparticles ranged in size from 2-20 nm and were crystallographically aligned with the host sapphire. Specimens were irradiated with Xe and Pt ions, and the microstructural evolution of the nanoclusters was investigated by transmission electron microscopy. With increasing Pt or Xe ion dose, the Co nanoparticles lost their initially excellent faceting, although they remained crystalline. The host Al2O3 became amorphous and the resulting microstructure consisted of a buried amorphous layer containing the still-crystalline Co nanoparticles. EDS mapping and electron diffraction were used to determine the distribution of the implanted species, and the magnetic properties of the composite were measured with a SQUID magnetometer. The results show that ion beams can be applied to modify and control the properties of ferromagnetic nanocomposites, and, combined with lithographic techniques, will find applications in exercising fine-scale spatial control over the properties of magnetic materials.

BIC Formation and Boron Diffusion in Relaxed Si0.8Ge0.2

2004 ◽  
Vol 810 ◽  
Author(s):  
R. T. Crosby ◽  
L. Radic ◽  
K. S. Jones ◽  
M. E. Law ◽  
P.E. Thompson ◽  
...  
Keyword(s):  
Surface Region ◽  
Extended Defects ◽  
Defect Structures ◽  
Boron Diffusion ◽  
Plan View ◽  
Near Surface ◽  
Transmission Electron ◽  
Secondary Ion ◽  
Ion Implanted

ABSTRACTThe relationships between Boron Interstitial Cluster (BIC) evolution and boron diffusion in relaxed Si0.8Ge0.2 have been investigated. Structures were grown by Molecular Beam Epitaxy (MBE) with surface boron wells of variant composition extending 0.25 [.proportional]m into the substrate, as well as boron marker layers positioned 0.50 [.proportional]m below the surface. The boron well concentrations are as follows: 0, 7.5×1018, 1.5×1019, and 5.0×1019 atoms/cm3. The boron marker layers are approximately 3 nm wide and have a peak concentration of 5×1018 atoms/cm3. Samples were ion implanted with 60 keV Si+ at a dose of 1×1014 atoms/cm2 and subsequently annealed at 675°C and 750°C for various times. Plan-view Transmission Electron Microscopy (PTEM) was used to monitor the agglomeration of injected silicon interstitials and the evolution of extended defects in the near surface region. Secondary Ion Mass Spectroscopy (SIMS) concentration profiles facilitated the characterization of boron diffusion behaviors during annealing. Interstitial supersaturation conditions and the resultant defect structures of ion implanted relaxed Si0.8Ge0.2 in both the presence and absence of boron have been characterized.

scholarly journals Effect of Photo-Assisted RIE Damage on GaN

2003 ◽  
Vol 8 ◽  
Author(s):  
Z. Mouffak ◽  
N. Medelci-Djezzar ◽  
C. Boney ◽  
A. Bensaoula ◽  
L. Trombetta
Keyword(s):  
Surface Chemistry ◽  
Breakdown Voltage ◽  
Schottky Diode ◽  
Preliminary Data ◽  
Surface Region ◽  
Gas Mixture ◽  
Ion Etching ◽  
Near Surface ◽  
Enhanced Diffusion ◽  
P Type

Reactive Ion Etching (RIE) and Photo-Assisted RIE (PA-RIE) induced damage in GaN using simple Schottky structures and a BCl3/Cl2/N2gas mixture have been investigated. Schottky diode I-V characteristics following different RF powers and exposure times show significant changes caused by damage. This damage results in a reduction of the reverse breakdown voltage VB in n-type GaN and an increase in VB for p-type GaN. Our preliminary data on the PA-RIE process points to much reduced damage levels compared to conventional RIE. This result may be due to a change in surface chemistry or to a photo-enhanced diffusion of defects into the GaN layer, leaving a cleaner near-surface region.

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