Saint-Martin-de-Fontenay, France
Saint-Martin-de-Fontenay, France

Time filter

Source Type

Cowern N.E.B.,Northumbria University | Simdyankin S.,Northumbria University | Ahn C.,Northumbria University | Bennett N.S.,Northumbria University | And 9 more authors.
Physical Review Letters | Year: 2013

B diffusion measurements are used to probe the basic nature of self-interstitial point defects in Ge. We find two distinct self-interstitial forms - a simple one with low entropy and a complex one with entropy ∼30 k at the migration saddle point. The latter dominates diffusion at high temperature. We propose that its structure is similar to that of an amorphous pocket - we name it a morph. Computational modeling suggests that morphs exist in both self-interstitial and vacancylike forms, and are crucial for diffusion and defect dynamics in Ge, Si, and probably many other crystalline solids. © 2013 American Physical Society.

Sermage B.,Probion Analysis | Essa Z.,Probion Analysis | Taleb N.,Probion Analysis | Quillec M.,Probion Analysis | And 6 more authors.
Journal of Applied Physics | Year: 2016

The electrochemical capacitance voltage technique has been used on highly boron doped SiGe and Si layers. Although the boron concentration is constant over the space charge depth, the 1/C2 versus voltage curves are not linear. They indeed present a negative curvature. This can be explained by the existence of deep acceptors which ionise under a high electric field (large inverse voltage) and not at a low inverse voltage. The measured doping concentration in the electrochemical capacitance voltage increases strongly as the inverse voltage increases. Thanks to a comparison with the boron concentration measured by secondary ions mass spectrometry, we show that the relevant doping concentrations in device layers are obtained for small inverse voltage in agreement with the existence of deep acceptors. At the large inverse voltage, the measured doping can be more than twice larger than the boron concentration measured with a secondary ion mass spectroscopy. © 2016 Author(s).

Hartmann J.M.,University Grenoble Alpes | Hartmann J.M.,CEA Grenoble | Benevent V.,CEA Grenoble | Andre A.,University Grenoble Alpes | And 12 more authors.
ECS Journal of Solid State Science and Technology | Year: 2014

We have developed an innovative 500°C process for the selective deposition of SiGe:B Raised Sources and Drains (RSDs).We have first of all studied on blanket Si wafers the in-situ boron doping of SiGe with Si2H6, GeH4 and B2H6. A growth rate increase by a factor higher than 4 together with a Ge concentration decrease from 45% down to 28% occurred as the diborane mass-flow increased (at 500°C, 20 Torr). Very high substitutional boron concentrations were achieved (~5 × 1020 cm-3) in layers that were single crystalline and flat. Adding large amounts of HCl to the gaseous mixture did not yield the selectivity aimed for on SiO2-covered Si wafers, however. To that end, we have thus benchmarked various 500°C Cyclic Deposition / Etch (CDE) processes. 12 cycles CDE processes were characterized by HCl etch rates of poly-SiGe:B that were too low to be of any practical use or yielded 3 dimensional SiGe:B layers on Si(001). Straightforward Deposition / Etch (DE) processes, with the HCl selective etch of poly-SiGe:B carried out at 740 Torr (i.e. atmospheric pressure), enabled us by contrast to achieve selectivity on SiO2 while retaining single crystalline and slightly rough SiGe:B layers. Those DE processes were tested on patterned Silicon-On-Insulator substrates with gate stacks. Longer HCl etch times than the ones identified on blanket wafers were key in getting rid of poly-SiGe:B on top of dielectrics covered surfaces; rather smooth, facetted SiGe:B RSDs were obtained in the end. © 2014 The Electrochemical Society.

Aubin J.,University Grenoble Alpes | Aubin J.,CEA Grenoble | Hartmann J.M.,University Grenoble Alpes | Hartmann J.M.,CEA Grenoble | And 4 more authors.
Semiconductor Science and Technology | Year: 2015

We have investigated the feasibility of selectively growing SiGe:B layers at 450 °C, 20 Torr in a 300 mm industrial reduced pressure chemical vapor deposition tool. A reduced H2 carrier gas mass-flow has been used in order to have acceptable growth rates at such a temperature, which is very low indeed. We have first of all studied on blanket Si wafers the in situ boron doping of SiGe with Si2H6, GeH4 and B2H6. A growth rate increase by a factor close to 7 together with a Ge concentration decrease from 53% down to 32% occurred as the diborane mass-flow increased. Very high B+ ion concentrations were obtained in layers that were single crystalline and smooth. Their concentration increased almost linearly with the B2H6 mass-flow, from 1.8 up to 8.3 × 1020 cm-3. The associated resistivity dropped from 0.43 down to 0.26 mΩ cm. We have then tested whether or not selectivity versus SiO2 could be achieved by adding various amounts of HCl to Si2H6 + GeH4 +B2H6. Single crystalline growth rates of intrinsic SiGe(:B) on Si were very similar to poly-crystalline growth rates on SiO2-covered substrates irrespective of the HCl flow. Straightforward selectivity was thus not feasible with a co-flow approach. As a consequence, a 450 °C deposition/etch (DE) process was evaluated. Growth occurred at 20 Torr with the above-mentioned chemistry, while the selective etch of poly-SiGe:B versus c-SiGe:B was conducted at 740 Torr with a medium HCl mass-flow (F(HCl)/F(H2) = 0.2) and a high H2 flow. A 2.2 etch selectivity was achieved while retaining single crystalline if slightly rough SiGe:B layers. © 2015 IOP Publishing Ltd.

Cristiano F.,Roche Holding AG | Shayesteh M.,Tyndall National Institute | Duffy R.,Tyndall National Institute | Huet K.,LASSE DaiNippon Screen | And 10 more authors.
Materials Science in Semiconductor Processing | Year: 2016

Defect evolution and dopant activation are intimately related to the use of ion implantation and annealing, traditionally used to dope semiconductors during device fabrication. Ultra-fast laser thermal annealing (LTA) is one of the most promising solutions for the achievement of abrupt and highly doped junctions. In this paper, we report some recent investigations focused on this annealing method, with particular emphasis on the investigation of the formation and evolution of implant/anneal induced defects and their impact on dopant activation. In the case of laser annealed Silicon, we show that laser anneal favours the formation of "unconventional" (001) loops that, following non-melt anneals, act as carrier scattering centres, leading to carrier mobility degradation. In contrast, in the case of melt anneals, the molten region itself is of excellent crystalline quality, defect-free and with very high activation rates. As for laser annealed Germanium, we studied in detail the amorphous to crystalline Ge phase transition as a function of the increasing LTA energy density and we found that using LTA, very high carrier concentrations (above 1020 cm-3) were achieved in As doped regions, which are unachievable with conventional rapid thermal annealing (RTA) processes. © 2015 Elsevier Ltd. All rights reserved.

Essa Z.,STMicroelectronics | Essa Z.,Roche Holding AG | Essa Z.,Toulouse 1 University Capitole | Cristiano F.,Roche Holding AG | And 16 more authors.
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2014

BF3 plasma immersion ion implantation (PIII) is a promising technique in the race for highly boron doped P+/N ultra-shallow junctions (USJs) in complementary metal oxide semiconductor (CMOS) silicon technologies. Implantation conditions used in BF3 PIII lead to high super-saturations (≥1 × 1020 cm-3) of both boron and silicon interstitial atoms in the implantation region. In such conditions, very large loop-shaped boroninterstitial clusters (BICs) are formed during subsequent thermal anneals, as confirmed by transmission electron microscopy (TEM) measurements. In this study, amorphizing BF3 PIII implants (10 keV, 5 × 1015 cm-2) followed by different thermal anneals were carried out in order to investigate the large BICs precipitation. A "large BICs" model based on moments approach allowed to reproduce the experimental data including boron diffusion profiles (obtained by SIMS) and boron electrical activation obtained by Hall effect sheet resistance measurements. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Qiu Y.,Roche Holding AG | Cristiano F.,Roche Holding AG | Huet K.,Excico Inc. | Mazzamuto F.,Excico Inc. | And 7 more authors.
Nano Letters | Year: 2014

Damage evolution and dopant distribution during nanosecond laser thermal annealing of ion implanted silicon have been investigated by means of transmission electron microscopy, secondary ion mass spectrometry, and atom probe tomography. Different melting front positions were realized and studied: nonmelt, partial melt, and full melt with respect to the as-implanted dopant profile. In both boron and silicon implanted silicon samples, the most stable form among the observed defects is that of dislocation loops lying close to (001) and with Burgers vector parallel to the [001] direction, instead of conventional {111} dislocation loops or {311} rod-like defects, which are known to be more energetically favorable and are typically observed in ion implanted silicon. The observed results are explained in terms of a possible modification of the defect formation energy induced by the compressive stress developed in the nonmelted regions during laser annealing. © 2014 American Chemical Society.

Cristiano F.,Roche Holding AG | Qiu Y.,Roche Holding AG | Bedel-Pereira E.,Roche Holding AG | Huet K.,Excico Inc. | And 8 more authors.
2014 International Workshop on Junction Technology, IWJT 2014 | Year: 2014

The formation of extended defects and their impact on dopant activation in nanosecond laser annealed silicon is investigated. It is found that laser anneal favours the formation of 'unconventional' (001) loops (typically not expected to occur in ion implanted silicon). (001) loops are formed near the liquid-solid interface (in the non-molten side region). Following non-melt anneals, these loops act as scattering centres, leading to carrier mobility degradation. In contrast, in the case of melt anneals, the molten region itself is of excellent crystalline quality, free of any large defects and leads to very high activation rates. Full melting of the implanted region leads to an almost perfectly recrystallized layer. Finally, we demonstrate how the internal stress generated in silicon during ultra-fast laser annealing in the ns regime can modify the fundamental mechanisms of defect formation and lead to the formation of these 'unconventional' loops. © 2014 IEEE.

Essa Z.,STMicroelectronics | Essa Z.,CNRS Laboratory for Analysis and Architecture of Systems | Cristiano F.,CNRS Laboratory for Analysis and Architecture of Systems | Spiegel Y.,IBS | And 10 more authors.
AIP Conference Proceedings | Year: 2012

In the race for highly doped ultra-shallow junctions (USJs) in complementary metal oxide semi-conductor (CMOS) technologies, plasma immersion ion implantation (PIII) is a promising alternative to traditional beamline implantation. Currently, no commercial technology computer aided design (TCAD) process simulator allows modeling the complete USJ fabrication process by PIII, including as-implanted dopant profiles, damage formation, dopant diffusion and activation. In this work, a full simulation of a p-type BF3 PIII USJ has been carried out. In order to investigate the various physical phenomena mentioned above, process conditions included a high energy/high dose case (10 kV, 5×1015 cm-2), specifically designed to increase damage formation, as well as more technology relevant implant conditions (0.5 kV) for comparison. All implanted samples were annealed at different temperatures and times. As implanted profiles for both boron and fluorine in BF3 implants were modeled and compared to Secondary Ion Mass Spectrometry (SIMS) measurements. Amorphous/crystalline (a/c) interface depths were measured by transmission electron microscopy (TEM) and successfully simulated. Diffused profiles simulations agreed with SIMS data at low thermal budgets. A boron peak behind the a/c interface was observed in all annealed SIMS profiles for the 10 kV case, indicating boron trapping from EOR defects in this region even after high thermal budgets. TEM measurements on the annealed samples showed an end of range (EOR) defects survival behind the a/c interface, including large dislocation loops (DLs) lying on (001) plane parallel to the surface. In the last part of this work, activation simulations were compared to Hall measurements and confirmed the need to develop a (001) large BICs model. © 2012 American Institute of Physics.

Loading Probion Analysis collaborators
Loading Probion Analysis collaborators