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In this work, a wafer-scale fabrication of biologically sensitive Si nanowire FET is demonstrated for pH sensing and electrical detection of DNA hybridization. Based on conventional “top-down” CMOS compatible technology, our bioFETs explore a wide range of design (nanowires [NW], nanoribbons [NR], and honeycomb [HC] structures) with opening access scaled down to only 120 nm. After device fabrication, I DS -V BG transfer and I DS -V DS output characteristics show a conventional n-type FET behavior with an I ON /I OFF value higher than 105, as well as an increase of threshold voltage as the NW width is reduced. Then, using a capacitive coupling in our dual-gated Si bioFETs, the pH sensitivity is enhanced with a pH response up to 600 mV/pH. Finally, the increase of threshold voltage of n-type SiNWs due to hybridized target DNA molecules is successfully detected.

The aim of this paper is to present the 3D-sequential integration and its main prospective application sectors. The presentation will also give a synoptic view of all the key enabling process steps required to build high performance Si CMOS integrated by 3D-sequential with thermal budget preserving the integrity of active devices and interconnects and will sketch a status and prospect on current low temperature device performance.

In this paper, we experimentally demonstrate, for the first time, gate-all-around (GAA) nanosheet transistors with a record number of stacked channels. Seven levels stacked nanosheet (NS) GAA transistors fabricated using a replacement metal gate process, inner spacer and self-aligned contacts show an excellent gate controllability with extremely high current drivability $(3\mathrm{mA}/\mu \mathrm{m}\ \mathrm{at}\ \mathrm{V}_{\mathrm{DD}}=1\mathrm{V})$ and a 3 x improvement in drain current over usual 2 levels stacked- NS GAA transistors.

In this contribution, we report on the growth of Ge inside extremely thin 16-nm thick cavities through selective lateral growth of Ge on 300 mm silicon-on-insulator (0 0 1) substrates. We showed that the density of defects depends on the cavity shape, with extended defects such as micro-twins and stacking faults observed on the top surface along the 〈1 1 0〉 directions when the Si/Ge growth interface is along the 〈1 1 0〉 directions. The optimization of the cavity shape, by tuning the etching conditions, leads to a significant reduction of the defects in the Ge nanostructures, and this approach paves the road towards the co-integration of Si and Ge based devices.

International audience; Using a metal-organic tungsten based precursor, a fluorine-free tungsten thin film has been obtained. The process deposition recipe includes a plasma-enhanced CVD (PECVD) step and atomic layer deposition (ALD) cycles. A set of physicochemical characterizations including X-ray reflectivity (XRR), in-plane X-ray diffraction (XRD), wavelength dispersive X-ray fluorescence (WDXRF), plasma profiling time of flight mass spectrometry (PPTOFMS) and microscope observations has been realized in order to study the W thin film structure and properties. The film is perfectly conformal whatever the structure size investigated (from tens of nanometers to micrometers wide). It was also highlighted that the F-free W film exhibits the lowest electrical resistivity phase (α-W) but is not pure. Indeed, in addition to a top surface oxidation, a layer located at the W film / substrate interface is present. This interface layer (IL) contains impurities, including carbon and oxygen, due to ligand decomposition. This IL might be deposited during the soak step or during the PECVD step. The W liner with thicknesses ranging from 3 to 4 nm has been implemented on PCRAM structures in order to evaluate its impact on contact plug resistivity. First electrical results are promising and demonstrate the interest of using a F-free low resistance W liner. At the aspect ratio studied, the gain in terms of contact plug resistivity is about 20% compared to the process of reference using a TiN liner. Modeling shows that this benefit is mainly due to the reduction of interface resistances.

3D sequential integration motivates the development of low temperature technological modules. Alternatively to classical non-selective annealing techniques, sub-microsecond laser annealing allows high temperature treatment of a sub-micrometer surface region while keeping the underneath structures at much lower temperature. In this contribution, we present recent advances in ultra-violet nanosecond laser annealing targeting monolithic 3D integration. Emphasis will be put on the demonstration of dopant activation in thin implanted SOI structures, simulating source and drain regions. Cu / ULK interconnects stability upon nanosecond laser annealing is also investigated.

This paper highlights the last technological breakthroughs achieved in the development of low temperature process modules at 500°C for 3D sequential integration. The two remaining process steps (low temperature gate stack and selective silicon raised source drain epitaxy) that were considered as potential showstoppers for this technology have shown decisive progress very recently.

For the first time, a comprehensive study going from the integration of 3D stacked nanosheets Gate-All-Around (GAA) MOSFET devices to SPICE modeling is proposed. Devices have been successfully fabricated on SOI substrates using a replacement high- $\kappa$ metal gate process and self-aligned-contacts. Back-biasing is herein efficiently used to highlight a drastic improvement of electrostatics in the upper GAA Si channels. Advanced electrical characterization of these devices enabled us to calibrate a new version of physical compact model (LETI-NSP) in order to assess the performance of ring oscillators for different configurations of GAA FETs integrating up to 8 vertically stacked Si channels.

To set up specification for 3D monolithic integration, for the first time, the thermal stability of state-of-the-art FDSOI (Fully Depleted SOI) transistors electrical performance is quantified. Post fabrication annealings are performed on FDSOI transistors to mimic the thermal budget associated to top layer processing. Degradation of the silicide for thermal treatments beyond 400 °C is identified as the main responsible for performance degradation for PMOS devices. For the NMOS transistors, arsenic (As) and phosphorus (P) dopants deactivation adds up to this effect. By optimizing both the n-type extension implantations and the bottom silicide process, thermal stability of FDSOI can be extended to allow relaxing upwards the thermal budget authorized for top transistors processing.

In this contribution, we report on the growth of horizontal Ge nanowires inside extremely thin tunnels surrounded by oxide. This is achieved through selective lateral growth of Ge on silicon-on-insulator (001) substrates. The 16 nm high tunnels are formed by HCl vapor etching of Si followed by Ge growth in the same epitaxy chamber. First, the benefit of growing the Ge nanowires at high temperature was highlighted to homogenize the length of the nanowires and achieve a high growth rate. Afterwards, we showed that increasing the tunnel depth led to a significant reduction in the growth rate. Finally, transmission electron microscopy showed that no defects were present in the Ge nanowires. These results are encouraging for the planar co-integration of heterogeneous materials on Si.In this contribution, we report on the growth of horizontal Ge nanowires inside extremely thin tunnels surrounded by oxide. This is achieved through selective lateral growth of Ge on silicon-on-insulator (001) substrates. The 16 nm high tunnels are formed by HCl vapor etching of Si followed by Ge growth in the same epitaxy chamber. First, the benefit of growing the Ge nanowires at high temperature was highlighted to homogenize the length of the nanowires and achieve a high growth rate. Afterwards, we showed that increasing the tunnel depth led to a significant reduction in the growth rate. Finally, transmission electron microscopy showed that no defects were present in the Ge nanowires. These results are encouraging for the planar co-integration of heterogeneous materials on Si.

International audience; This paper presents recent progress on Gate-All-Around (GAA) stacked-NanoWire (NW) / NanoSheet (NS) MOSFETs. Key technological challenges will be discussed and recent research results presented. Width-dependent carrier mobility in Si NW/NS and FinFET will be analyzed, and intrinsic performance and design considerations of GAA structures will be discussed and compared to FinFET devices with a focus on electrostatics, parasitic capacitances and different layout options. The results show that more flexibility can be achieved with stacked-NS transistors in order to manage power-performance optimization.

For the first time the thermal stability of a new fluorine-free (F-free) W barrier coupled with W interconnections enabling 22% line 1 resistance improvement is evaluated in view of 3D VLSI integration. Integrated with ULK, no resistance nor lateral capacitance degradation is observed up to 550°C 5h while preserving good reliability. For additional thermal stability a TEOS/W stability is demonstrated up to 600°C 2h. Both types of interconnection stacks have been successfully integrated on devices with 28nm design rules and show similar performance for MOSFETs and Ring Oscillators (RO) as compared to the ULK/Cu stack. Finally, iBEOL guidelines are given at the end in view of 3D sequential integration.

This work provides breakthroughs in key technological modules for high performance and reliable 3D Sequential Integration with intermediate BEOL (iBEOL) in-between tiers. We demonstrate that (i) a high-quality solid phase epitaxy process is possible at 500°C, (ii) TiN native oxide removal prior to poly deposition leads to an improvement in gate stack reliability below 525°C and (iii) state-of-the-art SiOCH ULK in iBEOL is reliable up to 550°C 5h with W metal lines. A process integration is thus proposed to match the process windows of bottom layers (bottom FET and iBEOL) stability and top devices performance and reliability, opening perspectives for a wide range of applications and technologies using 3D Sequential Integration.

Stacking N over CMOS devices using 3D Sequential CoolCube™ Integration has been shown promising for the scaling of 6T SRAMs. By transposing one pass-gate and one pull-down NMOS to the top layer, a cell footprint reduction of 27% could be obtained, leading to a 3D vias density over 108/mm2 achievable. In addition, we presented N-type devices fabricated below 630°C yielding quasi-equivalent performances as high temperature ones while fulfilling the PBTI and hot-carrier effects reliability requirements, comforting the viability of N over CMOS approach.

In this paper, the recent advances in low temperature process in view of 3D VLSI integration are reviewed. Thanks to the optimization of each low temperature process modules (dopant activation, gate stack, epitaxy, spacer deposition) and silicide stability improvement, the top layer thermal budget fabrication has been decreased in order to satisfy the requirements for 3D VLSI integration.

In this paper, the energy process window of nanosecond (ns) laser annealing for junctions activation has been determined for several dopants (As, P, BF2). The different recrystallization states observed when tuning laser energy density are explained by numerical simulations. Within these conditions, the laser impact on the thermal stability of ULK/copper inter-tiers interconnections has been evaluated for a 28nm node backend metal 1 design rules technology both from morphological and electrical perspectives. This study highlights the interest of ns laser anneal for CoolCube™ 3D integration.

In this paper, we demonstrate low junction leakage for Fully Depleted Silicon On Insulator (FDSOI) devices fabricated with a low thermal budget (⩽650 °C), which commonly exhibit leakage problems due to the presence of defects in or close to depletion regions. We show through both experimental data and Kinetic Monte Carlo (KMC) simulations that the reduction of the film thickness and Raised Source Drain (RSD) allow the elimination of defects in critical regions in spite of the reduced thermal budget in the very early stage of the anneal. KMC simulations also show that defects are annealed-out in this critical region even for 500 °C anneals. Low temperature process appears then as a suitable process for advanced devices.

We have evaluated various Cyclic Selective Epitaxial Growth/Etch (CSEGE) processes in order to grow “mushroom-free” Si and SiGe:B Raised Sources and Drains (RSDs) on each side of ultra-short gate length Extra-Thin Silicon-On-Insulator (ET-SOI) transistors. The 750 °C, 20 Torr Si CSEGE process we have developed (5 chlorinated growth steps with four HCl etch steps in-between) yielded excellent crystalline quality, typically 18 nm thick Si RSDs. Growth was conformal along the Si3N4 sidewall spacers, without any poly-Si mushrooms on top of unprotected gates. We have then evaluated on blanket 300 mm Si(001) wafers the feasibility of a 650 °C, 20 Torr SiGe:B CSEGE process (5 chlorinated growth steps with four HCl etch steps in-between, as for Si). As expected, the deposited thickness decreased as the total HCl etch time increased. This came hands in hands with unforeseen (i) decrease of the mean Ge concentration (from 30% down to 26%) and (ii) increase of the substitutional B concentration (from 2 × 1020 cm−3 up to 3 × 1020 cm−3). They were due to fluctuations of the Ge concentration and of the atomic B concentration [B] in such layers (drop of the Ge% and increase of [B] at etch step locations). Such blanket layers were a bit rougher than layers grown using a single epitaxy step, but nevertheless of excellent crystalline quality. Transposition of our CSEGE process on patterned ET-SOI wafers did not yield the expected results. HCl etch steps indeed helped in partly or totally removing the poly-SiGe:B mushrooms on top of the gates. This was however at the expense of the crystalline quality and 2D nature of the ∼45 nm thick Si0.7Ge0.3:B recessed sources and drains selectively grown on each side of the imperfectly protected poly-Si gates. The only solution we have so far identified that yields a lesser amount of mushrooms while preserving the quality of the S/D is to increase the HCl flow during growth steps.

3D VLSI with a CoolCube™ monolithic integration flow allows vertically stacking several layers of devices with a unique connecting via density above tens of million/mm2. This results in increased devices density and gains in power and performance thanks to wire-length reduction without the extra cost associated to transistor scaling. In addition to power saving, this true 3D integration opens perspectives in terms of heterogeneous integration. We will review the opportunities brought by CoolCube™ and will present the most advanced technological demonstration of 3D CMOS over CMOS CoolCube™ integration.

For the first time, a full 3D CMOS over CMOS CoolCube™ integration is demonstrated with a top level compatible with state of the art high performance FDSOI (Fully-Depleted Silicon On Insulator) process requirements such as High-k/metal gate or raised source and drain. Functional 3D inverters with either PMOS or NMOS on the top level are highlighted. Furthermore, Si layer transfer above a 28nm W Metal 1 level of an industrial short loop and the return in a front end environment is presented, confirming the industrial compatibility of CoolCube™ integration.

This work highlights recent advances in 3D VLSI integration. A review of low temperature process modules development such as junctions, spacers and salicidation is presented. Finally, for the first time, a full CMOS over CMOS 3D VLSI integration on 300mm wafers is demonstrated with a top level compatible with state of the art high performance FDSOI (Fully-Depleted Silicon On Insulator) process requirements such as High-k/metal gate or raised source and drain.

In 3D sequential integration, the top transistor thermal budget must be reduced to preserve bottom MOSFET performance. In order to relax this thermal budget limitation, the thermal stability of the bottom level must be increased, especially for the silicide. In that purpose, Ni0.9Co0.1 alloy is proposed to replace the current Ni0.85Pt0.15 silicide. For the first time, this Ni0.9Co0.1 salicide has been integrated on pMOS FDSOI transistors with state of the art process leading to performance improvements compared to the standard Ni0.85Pt0.15 salicide. In this study, the cobalt incorporation into the salicide has been investigated to enhance its thermal stability.

After a short reminder of the principle of monolithic 3D integration, this paper firstly reviews the main technological challenges associated to this integration and proposes solutions to assess them. Wafer bonding is used to have perfect crystalline quality of the top layer at the wafer scale. Thermally stabilized silicide is developed to use standard salicidation scheme in the bottom layer. Finally a fully depleted SOI low temperature process is demonstrated for top layer processing (overall temperature kept below 650^oC). In a second part the electrical results obtained within this integration scheme are summarized: mixed Ge over Si invertor is demonstrated and electrostatic coupling between top and bottom layer is used to shift the threshold voltage of the top layer. Finally circuit opportunities such as stabilized SRAM or gain in density are investigated.

In this brief, the hole transport properties of narrow-width germanium-on-insulator (GeOI) pMOSFETs are investigated. We report, for the first time, +65% low-field hole mobility enhancement in narrow-width (0.29-mum effective widthW eff) versus large-width (10- mum W eff) GeOI mesa-isolated devices. The observed enhancement, which is independent of the device length down to 90 nm, is attributed to improved sidewall transport properties resulting in higher hole mobility on the sides than on the top of the devices. At high inversion charge density N inv~ 1013 cm-2, + 55% hole effective mobility improvement is preserved. The top and side low-field mobilities ( mutop and muside, respectively) were extracted, showing + 90% mobility improvement at the sides (mutop = 125 cm2/V middots-1 and muside= 240 cm2/V middots-1).

P. Batude, M. Vinet, L. Clavelier, A. Pouydebasque, C. Tabone, A. Roman, L. Baud, V. Carron, F. Nemouchi, L. Sanchez, and S. Deleonibus. CEA-LETI, Minatec, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France. perrine.batude@cea.fr 3D integration is regularly mentioned for its potential in decreasing interconnection delay, and for the density gain brought by stacking several transistors layers. An additional benefit of 3D integration lies in an independent optimization of n-FET and p-FET allowed by stacking entire p-FET onto n-FET layers. In this integration scheme, connecting the layers at the transistor scale is absolutely mandatory. 3D monolithic integration, with its high alignment performance fulfils this requirement whereas parallel integration falls short in this aspect (best alignment performance at 1 sigma ~0.5μm). To achieve 3D monolithic integration, some issues such as realization of high quality top film, high stability bottom FET, low TB (Thermal Budget) top FET still have to be solved. In this paper, a 3D monolithic process flow relying on molecular Wafer Bonding (WB) (fig.1) is proposed and breakthroughs in the critical steps are presented. It allows full enhancement of n and p-FET performance through material choice, strain options, surface and channel orientation and metal workfunction tuning. Note that WB, contrary to other techniques for upper thin film realisation based on recristallisation, offers the possibility to co-integrate different surface and channel orientations. Furthermore this mature process step leads to a high quality crystalline top film with low TB. For the top crystalline layer realization, a Ge or Si on insulator substrate is bonded at room temperature on the fully processed bottom transistor layer after planarization of its topology (fig.1(b)). A low temperature anneal (200°C) is performed to strengthen the bonding interface before mechanical substrate removal. The bonding is found of excellent quality with bonding energy of 900 mJm (mazzara method) and clean acoustic and infrared characterisation as shown in figure 2 (a,b) . Note that the Inter Layer Dielectric (ILD) thickness (fig.2(c)) is thinned down to 100 nm and allows dense 3D contacts. Indeed this additional depth, specific to 3D technology must be minimized to enable the contact scalability as its etching and filling become critical. To spare the bottom FET from high temperature anneal for top transistor dopant activation, which would have detrimental impact on its performance, SPE (Solid Phase Epitaxial) on thin SOI films (

session 5: 3D Systems and Packaging; International audience; 3D VLSI with a CoolCube™ integration allows vertically stacking several layers of devices with a unique connecting via density above a million/mm 2 . This results in increased density with no extra cost associated to transistor scaling, while benefiting from gains in power and performance thanks to wire-length reduction. CoolCube™ technology leads to high performance top transistors with Thermal Budgets (TB) compatible with bottom MOSFET integrity. Key enablers are the dopant activation by Solid Phase Epitaxy (SPE) or nanosecond laser anneal, low temperature epitaxy, low k spacers and direct bonding. New data on the maximal TB bottom MOSFET can withstand (with high temperatures but short durations) offer new opportunities for top MOSFET process optimization.

For the first time the maximum thermal budget of in-situ doped source/drain State Of The Art (SOTA) FDSOI bottom MOSFET transistors is quantified to ensure transistors stability in Sequential 3D (CoolCube™) integration. We highlight no degradation of Ion/Ioff trade-off up to 550°C. Thanks to both metal gate work-function stability especially on short devices and silicide stability improvement, the top MOSFET temperature could be relaxed up to 500°C. Laser anneal is then considered as a promising candidate for junctions activation. Based on in-depth morphological and electrical characterizations it demonstrates very promising results for high performance Sequential 3D integration.

session: FDSOI; International audience; Low temperature (LT) activation on Fully Depleted Silicon On Insulator by SPER is needed for 3D sequential integration and also provides interest to obtain highly doped abrupt junctions in the standard planar technology. In this work, through the confrontation of electrical data and KMC process simulation we identify the efficient lever to optimize the low temperature device performance. This work evidences that the most suitable integration for LT FET implies a LDD implantation before the first spacer and the raised source drain epitaxy.

Monolithic or sequential 3D Integration is a powerful technological enabler for actual 3D IC design as the stacked layers can be connected at the transistor scale. This paper reviews the opportunities brought by M3DI and highlights the applications benefiting from this small 3D contact pitch. It also presents the technological challenges of this concept and offers a general overview of the potential solutions to obtain a high performance low temperature top transistor while keeping bottom MOSFET integrity.

Using a novel process flow, we managed to cointegrate several devices on the same wafer; single gate (SG), ground plane (GP), perfectly aligned double gate (DG), misaligned DG and oversized back-gate DG. This paper reports the experimental evaluation of the gate architectures influence on the performance of silicon-on-insulator MOSFETs. DG MOSFETs, with gate lengths down to 40 nm, are experimentally compared to SG and GP MOSFETs. Short-channel effect (SCE) control, static performance and mobility are quantified for each architecture. When compared to SG and GP transistors, the DG transistor shows the best SCE control and performance as predicted by simulations. Gate coupling is demonstrated to be a sensitive and a nondestructive method to evaluate the real on-wafer alignment. Using this method, we report an experimental analysis of gate misalignment influence on DG MOSFETs' performance and SCE. It is found that misalignment primarily affects the subthreshold parameters due to an electrostatic control loss. The DG MOSFET with a slightly oversized back gate (10 nm on each side of the top gate) is a promising solution, if a 10% loss in dynamic performance can be tolerated.

Thanks to ultimate Si nMOSFETs with physical gate length down to 16 nm, the main challenges related to conventional transistors have been estimated. Short channel effect control is difficult below 40 nm due to the large TED of BF 2 halos. Nevertheless drain current higher than 800 μA/μm @ V d =1.5 V can be reached. Such performance is not a consequence of non-stationary effects since these are limited by the degradation of the low longitudinal field mobility on conventional short transistor. Ultimate transport is also analysed thanks to short and narrow devices. At low temperature, these MOSFETs are shown to operate like single electron transistors.

3D sequential integration of two stacked transistor levels has been recently demonstrated with success on 300 mm wafers with a maximum thermal budget approaching 650°C-20 minutes for the completion of the top level [1]. However, such thermal budget is still too high to avoid any degradation of the bottom transistors performance [2]. Thus, for several technological modules, such as dopant activation, gate stack formation, spacers deposition and source/ drain epitaxy, very low temperature processes must be developed. For low temperature junction activation, solid phase epitaxy regrowth (SPER) is a first option, with typical annealing conditions around 600°C-1 minute [1]. Sub-microsecond laser annealing is a second approach, with the capability to selectively heat a sub-µm surface region. In this paper, we review recent advances in UV pulsed laser annealing in view of 3D sequential integration. Based on 2D numerical simulations, we optimized the process structure for the upper source and drain activation and recrystallization upon laser annealing (wavelength: 308 nm), while trying to avoid any degradation of the bottom transistor. An anti-reflective capping layer over the top transistors is found to reduce laser energy absorption in the upper gate (Figure 1). The lower gate maximum temperature can be reduced down to 600°C (pulse duration: 160 ns) with a structure combining favorable bottom BOX and inter-level SiO2 thicknesses (Figure 2). Moreover, with a shorter laser pulse (80 ns), the bottom level temperature can even approach 500°C while the upper level layers reach 1200°C. To mimic the optimal structures with simple vehicle tests and evaluate the laser annealing process window for dopant activation, SOI structures (25 nm BOX, 23 nm top Si layer) have been implanted with As, BF2 or P, then capped with 30 nm SiN and annealed using SCREEN-LASSE LT-3100 system at various laser energy densities. Sheet resistance measurements combined with SIMS profiles and TEM cross-section observations (Figure 3) allowed us to identify the different regimes encountered as a function of the laser fluence. The process window starts when the whole region amorphized by implantation on top of the single crystalline thin seed layer is melt, and stops with the full SOI layer melt. Around the optimal energy density, we reached perfect crystal recovery and high dopant activation levels, comparable to those obtained with spike RTP. Concerning the laser pulse duration, a trade-off is to be found: The process window is reasonably large in case of a 160 ns pulse and becomes narrower with a 80 ns pulse but such shorter laser treatment is more favorable in terms of heat diffusion. To avoid global routing congestion, the 3D sequential architecture requires the introduction of inter-tier Back-End-Of-line (iBEOL) levels routing the bottom tier. As a consequence, such iBEOL needs to support the thermal budget applied for the top tier processing. Coupling numerical simulations with experimental tests on simplified structures, we investigated the impact of pulsed laser annealing on such inter-level metal interconnection. Based on 28 nm standard design rules, we integrated one metal level (Cu) using porous SiOCH as ultra-low-k dielectric and the appropriate barrier layers. Before submitting such structures to laser annealing, we deposited 50 nm or 120 nm inter-level SiO2 and 20 nm amorphous Si (a-Si) to simulate the top transistor level. According to simulations, above relaxed interconnect regions (large interconnect pitch), the average thermal conductivity of the stack is lower, promoting a slightly faster temperature rise in these regions, compared to more dense regions. A thicker inter-level oxide layer contributes to reduce the peak temperature of the Cu interconnects. Finally, line resistance and lateral capacitance measurements show no modification upon laser annealing, even with conditions leading to the melt of the top a-Si layer, for both 50 and 120 nm inter-level oxides (Figure 4). All these results provide guidelines for low temperature junction formation in a 3D sequential integration using nanosecond laser annealing, reinforcing this technique as a true alternative to SPER. References [1] L. Brunet et al., Proceedings of symposium on VLSI Technology (2016) 7573428. [2] C. Fenouillet-Béranger et al., Proceedings. of Intern. Electron Devices Meeting (2014) 7047121 [3] C. Fenouillet-Béranger et al., Proceedings of SOI-3D-Subthreshold Microelectr. Technol. Unified Conf. (2016) 7804375 [4] P. Acosta-Alba et al., Proceedings of. Ion Implant. Technol. Conf. (2016) [5] S. Kerdilès et al., 16th Intern. Workshop on Junction Technol. (2016) p.72 Figure 1

To set up specification for 3D monolithic integration, for the first time, the thermal stability of state-of-the-art FDSOI (Fully Depleted SOI) transistors electrical performance is quantified. Post fabrication annealings are performed on FDSOI transistors to mimic the thermal budget associated to top layer processing. Degradation of the silicide for thermal treatments beyond 400 °C is identified as the main responsible for performance degradation for PMOS devices. For the NMOS transistors, arsenic (As) and phosphorus (P) dopants deactivation adds up to this effect. By optimizing both the n-type extension implantations and the bottom silicide process, thermal stability of FDSOI can be extended to allow relaxing upwards the thermal budget authorized for top transistors processing.

session 8: Beyond CMOS; International audience; We present for the first time high performance Nanowire (NW) Tunnel FETs (TFET) obtained with a CMOS-compatible process flow featuring compressively strained Si 1-x Ge x (x=0, 0.2, 0.25) nanowires, Si 0.7 Ge 0.3 Source and Drain and High-K/Metal gate. Nanowire architecture strongly improves electrostatics, while low bandgap channel (SiGe) provides increased band-to-band tunnel (BTBT) current to tackle low ON current challenges. We analyse the impact of these improvements on TFETs and compare them to MOSFET ones. Nanowire width scaling effects on TFET devices are also investigated, showing a W -3 dependence of ON current (I ON ) per wire. The fabricated devices exhibit higher I ON than any previously reported TFET, with values up to 760μA/μm and average subthreshold slopes (SS) of less than 80mV/dec.

This paper reviews how the evolution of FDSOI planar architecture towards Trigate Nanowires leads to a natural Single Electron Transistor and Field Effect Transistor convergence at room temperature. On one hand, this convergence sets up technological specifications to preserve CMOS operation. On the other hand it opens the path to room temperature hybrid circuits based on single electron transistors and MOSFETs. Further on, single electron effects can be downscaled to the ultimate single atom transistors and we demonstrate the practical performance of electron pumps for metrologic applications.