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.

Suppression of Boron Transient Enhanced Diffusion in SiGe HBTs by Carbon Incorporation

1997 ◽  
Vol 469 ◽  
Author(s):  
L. D. Lanzerotti ◽  
J. C. Sturm ◽  
E. Stach ◽  
R. Hull ◽  
T. Buyuklimanli ◽  
...  
Keyword(s):  
Thermal Diffusion ◽  
Heterojunction Bipolar Transistors ◽  
Bipolar Transistors ◽  
Electrical Characteristics ◽  
Carbon Incorporation ◽  
Carbon Fractions ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Heavily Doped

ABSTRACTIn this paper we demonstrate, using both SIMS and transistor electrical characteristics, that substitutional carbon fractions of 0.5% in heavily doped Si0.8Ge0.2 base heterojunction bipolar transistors (HBTs) reduce both thermal diffusion and transient enhanced diffusion (TED) of boron. Furthermore we show that carbon suppresses TED of boron in carbon-free regions that surround the carbon layers.

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.

Transient Enhanced Diffusion of Dopants in Preamorphised Si Layers

1996 ◽  
Vol 439 ◽  
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.

Investigation of Fluorine Effect on the Boron Diffusion by Mean of Boron Redistribution in Shallow Delta-doped Layers

2004 ◽  
Vol 810 ◽  
Author(s):  
A. Halimaoui ◽  
J. M. Hartmann ◽  
C. Laviron ◽  
R. El-Farhane ◽  
F. Laugier
Keyword(s):  
Point Defects ◽  
Depth Profiling ◽  
Boron Diffusion ◽  
Enhanced Diffusion ◽  
Boron Doped ◽  
Transient Enhanced Diffusion ◽  
Sims Depth Profiling

ABSTRACTPreviously published articles have shown that co-implanted fluorine reduces transient enhanced diffusion of boron. However, it is not yet elucidated whether this effect is due to interaction of fluorine with point-defects or boron atoms. In this work, we have used boron redistribution in a shallow Delta-doped Si structures in order to get some insights into the role of fluorine in the boron diffusion. The structures consisted of 3 boron-doped layers separated by 40nm-thick undoped silicon. The samples were given to Ge preamorphization and F co-implant. SIMS depth profiling was used to analyse boron redistribution after annealing. The results we obtained strongly suggest that fluorine is not interacting with point-defects. The reduction in boron TED is most probably due to boron-fluorine interaction.

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.

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.

A New Practical Approach to Implement a Transient Enhanced Diffusion Model into an Fem-Based 2-D Process Simulator

1997 ◽  
Vol 490 ◽  
Author(s):  
Noriyuki Sugiyasu ◽  
Kaina Suzuki ◽  
Syuichi Kojima ◽  
Yasushi Ohyama
Keyword(s):  
Diffusion Model ◽  
Boron Diffusion ◽  
Combined Method ◽  
Solution System ◽  
Charge Neutrality ◽  
Robust Solution ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Vacancy Pair ◽  
Process Simulator

ABSTRACTWe have proposed a coupled and de-coupled combined method to solve partial differential equations for a transient enhanced diffusion model. In the case of a boron diffusion process, the sum of concentrations of interstitial Si and of impurity-interstitial pair, the sum of concentrations of vacancy and of impurity-vacancy pair and each chemical impurity concentration are kept constant. The charge neutrality law is also applied. This procedure has realized a robust solution system which is implemented into our in-house FEM-based 2-D process simulator, and transient enhanced diffusion simulations for a sub-quarter micron nMOSFET have been demonstrated.

Junction Depth Reduction of ion Implanted Boron in Silicon Through Fluorine ion Implantation

2000 ◽  
Vol 610 ◽  
Author(s):  
L. S. Robertson ◽  
P. N. Warnes ◽  
K. S. Jones ◽  
S. K. Earles ◽  
M. E. Law ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Species ◽  
Amorphous Layer ◽  
Experimental Conditions ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Transmission Electron ◽  
Species Effect ◽  
Boron Diffusivity

AbstractThe interaction between boron and excess silicon interstitials caused by ion implantation hinders the formation of ultra-shallow, low resistivity junctions. Previous studies have shown that fluorine reduces boron transient enhanced diffusion, however it is unclear whether this observed phenomenon is due to the fluorine interacting with the boron atoms or silicon self-interstitials. Amorphization of a n-type Czochralski wafer was achieved with a 70 keV Si+ implantation at a dose of 1×1015/cm2. The Si+ implant produced a 1500Å deep amorphous layer, which was then implanted with 1.12 keV 1×1015/cm2 B+. The samples were then implanted with a dose of 2×1015/cm2F+ at various energies ranging from 2 keV to 36 keV. Ellipsometry measurements showed no increase in the amorphous layer thickness from either the boron or fluorine implants. The experimental conditions allowed the chemical species effect to be studied independent of the implant damage caused by the fluorine implant. Post-implantation anneals were performed in a tube furnace at 750° C. Secondary ion mass spectrometry was used to monitor the dopant diffusion after annealing. Transmission electron microscopy (TEM) was used to study the end-of-range defect evolution. The addition of fluorine reduces the boron transient enhanced diffusion for all fluorine energies. It was observed that both the magnitude of the boron diffusivity and the concentration gradient of the boron profile vary as a function of fluorine energy.

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.

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