Emmanuel Jacques | Université de Rennes (original) (raw)

Papers by Emmanuel Jacques

Research paper thumbnail of High rectifying behavior in Al/Si nanocrystal-embedded SiOxNy/p-Si heterojunctions

Semiconductor Science and Technology, Mar 11, 2011

We examine the electrical properties of MIS devices made of Al/Si nanocrystal-SiO x N y /p-Si. Th... more We examine the electrical properties of MIS devices made of Al/Si nanocrystal-SiO x N y /p-Si. The J-V characteristics of the devices present a high rectifying behavior. Temperature measurements show that the forward current is thermally activated following the thermal diffusion model of carriers. At low reverse bias, the current is governed by thermal emission amplified by the Poole-Frenkel effect of carriers from defects located at the silicon nanocrystals/SiO x N y interfaces, whereas tunnel conduction in silicon oxynitride matrix dominates at high reverse bias. The devices exhibit a rectification ratio >10 4 for the current measured at V = ± 1 V. Study reveals that thermal annealing in forming gas (H 2 /N 2) improves the electrical properties of the devices due to the passivation of defects.

Research paper thumbnail of Front Cover: Electronic and Charge Transport Properties in Bridged versus Unbridged Nanohoops: Role of the Nanohoop Size (Chem. Eur. J. 41/2023)

Chemistry: A European Journal, Jun 14, 2023

Research paper thumbnail of Silicon Nanowires based devices for biological/chemical sensors applications

HAL (Le Centre pour la Communication Scientifique Directe), Jun 4, 2012

International audienc

Research paper thumbnail of Step-gate polysilicon nanowires field effect transistor compatible with CMOS technology for label-free DNA biosensor

Biosensors and Bioelectronics, Feb 1, 2013

Currently, detection of DNA hybridization using fluorescence-based detection technique requires e... more Currently, detection of DNA hybridization using fluorescence-based detection technique requires expensive optical systems and complex bioinformatics tools. Hence, the development of new low cost devices that enable direct and highly sensitive detection stimulates a lot of research efforts. Particularly, devices based on silicon nanowires are emerging as ultrasensitive electrical sensors for the direct detection of biological species thanks to their high surface to volume ratio. In this study, we propose innovative devices using step-gate polycrystalline silicon nanowire FET (poly-Si NW FETs), fabricated with simple and low cost fabrication process, and used as ultrasensitive electronic sensor for DNA hybridization. The poly-SiNWs are synthesized using the sidewall spacer formation technique. The detailed fabrication procedure for a step-gate NWFET sensor is described in this paper. Nocomplementary and complementary DNA sequences were clearly discriminated and detection limit to 1fM range is observed. This first result using this nano-device is promising for the development of low cost and ultrasensitive polysilicon nanowires based DNA sensors compatible with the CMOS technology.

Research paper thumbnail of Bottom-gate and Step-gate Polysilicon Nanowires Field Effect Transistors for Ultrasensitive Label-free Biosensing Application

Procedia Engineering, 2012

Simple and low-cost polycrystalline silicon nanowires field effect transistor (poly-SiNWFET) are ... more Simple and low-cost polycrystalline silicon nanowires field effect transistor (poly-SiNWFET) are fabricated using two different configurations: step-gate and back-gate. The nanowires are synthesized using the sidewall spacer formation technique compatible with the well-known CMOS technology. Probe DNA strands immobilization is performed by the functionalization of poly-SiNWs using APTES and glutaraldehyde. Hybridization phenomenon is detected on electrical characteristics of the poly-SiNWFETs. The first results demonstrate that these devices are promising tools for low-cost, real time and label-free DNA sensing with detection limit at 1fM.

Research paper thumbnail of Au-Catalyst Silicon Nanowires Synthesized by Vapor–Liquid–Solid Technique in a V-Shaped Groove: Application for Gas Sensors

Sensor Letters, Aug 1, 2013

ABSTRACT Au-catalyst Vapor–Liquid–Solid (VLS) silicon nanowires (SiNWs) with high density are syn... more ABSTRACT Au-catalyst Vapor–Liquid–Solid (VLS) silicon nanowires (SiNWs) with high density are synthesized on heavily doped polysilicon islands patterned on both sidewalls of the 〈100〉 oriented silicon substrate V-shaped groove. The resulting SiNWs network permits to interconnect two heavily doped polysilicon islands leading to the formation of a resistor inside the groove. The quantitative dynamic measurements under exposure of this device to a wide range of gas (ammonia) concentration (from 10 ppm to 350 ppm) were carried out and demonstrated the feasibility of highly sensitive SiNWs based resistors used as gas sensors.

Research paper thumbnail of Ammonia Sensors Based on Suspended Silicon Nanowires

Procedia Engineering, 2014

Research paper thumbnail of N‐type <i>in‐situ</i> doping effect on vapour‐liquid‐solid silicon nanowire properties for gas sensing applications

Physica status solidi, Feb 1, 2014

N‐type in‐situ doped SiNWs based resistors are fabricated and used as gas (ammonia) sensors. SiNW... more N‐type in‐situ doped SiNWs based resistors are fabricated and used as gas (ammonia) sensors. SiNWs are prepared by vapour‐liquid‐solid method (VLS) using gold as catalyst. In‐situ doping level is adjusted by varying the phosphine to silane mole ratio. Because SiNWs can act as sensitive units specific design is developed to allow large sensing areas, following a process fabrication compatible with a mass production planar layout. SiNWs doping effect on ammonia detection is carried out under controlled ammonia/nitrogen mixture varying from 2 ppm to 700 ppm. Results highlight that the relative response, Sg=(I0‐Ig)/I0, where I0 and Ig are the current values in vacuum and reactive ambient respectively, follows a linear behaviour. The relative sensitivity, (S=ΔSg/Δ[NH3]) decreases, whereas the sensitivity (SxI0) increases with the increase of the VLS SiNWs doping level. (© 2014 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Research paper thumbnail of Silicon nanowires synthesized by VLS technique in a V-shaped groove for gas sensing applications

HAL (Le Centre pour la Communication Scientifique Directe), May 14, 2012

International audienc

Research paper thumbnail of Fabrication et caractérisation électrique d'un capteur de gaz à base de nanofils de silicium suspendus

HAL (Le Centre pour la Communication Scientifique Directe), Nov 28, 2013

Cet article présente un TP proposé à des étudiants de masters ou filières d'écoles d'ingénieurs r... more Cet article présente un TP proposé à des étudiants de masters ou filières d'écoles d'ingénieurs relevant des nanosciences. Il s'agit de fabriquer en salle blanche un capteur de gaz à base d'un réseau de nanofils de silicium suspendus et de mesurer sa sensibilité à l'ammoniac. Les étudiants sont ainsi initiés à la fois à la fabrication technologique en salle blanche d'un composant, à la caractérisation électrique et structurale ainsi qu'à son application pour la détection de gaz.

Research paper thumbnail of In-situ doping influence on Vapor Liquid Solid Silicon nanowires electrical pRoperties for gas sensing application

HAL (Le Centre pour la Communication Scientifique Directe), May 27, 2013

International audienc

Research paper thumbnail of Silicon nanowires synthesis for chemical and biological sensors applications

HAL (Le Centre pour la Communication Scientifique Directe), Nov 13, 2013

Research paper thumbnail of Nanofils de silicium utilisés dans des capteurs chimiques et biologiques

HAL (Le Centre pour la Communication Scientifique Directe), Oct 3, 2011

Research paper thumbnail of Highly Flexible Microcrystalline Silicon n-Type TFT on PEN Bent to a Curvature Radius of 0.75 mm

IEEE Transactions on Electron Devices, Oct 1, 2015

Electrical and mechanical performances of microcrystalline silicon top-gate thin-film transistors... more Electrical and mechanical performances of microcrystalline silicon top-gate thin-film transistors (TFTs) on flexible substrate under high bending is presented. These devices are directly fabricated on 25-µm-thick Polyethylene naphthalate (PEN) at a maximum temperature of 180°C. Tensile and compressive bending are performed and revealed that the TFTs can hold curvature radii of 1.5 mm without losing their performance and 0.75 mm with lower electrical performances. The limiting factor on the flexibility is shown to be the mechanical behavior of silicon nitride film used as a gate insulator. These extremely high curvatures demonstrate the possibility to use silicon technology in foldable electronics. TFTs are also shown to fully recover their characteristics when reflattened after such very low curvature radii. It opens the way to fold in half an electronic circuit to be stored and reused when reflattened.

Research paper thumbnail of Polycristalline silicon nanowires based TFTs compatible with CMOS technology for chemical integrated sensors

HAL (Le Centre pour la Communication Scientifique Directe), Feb 25, 2015

International audienceThanks to their high surface to volume ratio, silicon nanowires (SiNWs) are... more International audienceThanks to their high surface to volume ratio, silicon nanowires (SiNWs) are good candidates as sensitive units for fabrication of high sensitive chemical sensors. SiNWs can be prepared by one of two approaches, “top-down“ and “bottom up”. In a bottom up strategy synthesis methods most developed are layer-by-layer self-assembly, Vapor Liquid Solid (VLS) and using matrix template. The main drawbacks of these synthesis methods for a 3D integration are the difficulty in control of size and positioning of the nanowires. In this case, nanowires need to be selectively collected and manipulated to be assembled in a planar layout. For the “top down” approach several advanced nanopatterning techniques were developed such as e-beam, atomic force microscopy (AFM), deep UV and nanoimprint lithographies, to obtain SiNWs. The main drawbacks of these advanced lithographic tools with nanometer size resolution rest on the high cost generated, and more generally the low throughput capability unsuitable with mass production. Because SiNWs synthesis can be compatible with the reproducible and reliable performances of the established silicon technology, SiNWs based sensor integration will allow a lower manufacturing cost, in addition to the advantageous electronic features of embedded detection and signal processing in silicon technology. The intrinsic reliability of the well-known semiconductor CMOS (Complementary Metal Oxide Semiconductor) process also guarantees reproducible and reliable performances. In our study, polycrystalline silicon nanowires are synthesized following the top-down approach using a classical fabrication method commonly used in microelectronic industry: the sidewall spacer formation technique. The feasibility of these polycristalline SiNWs with a curvature radius as low as 50 nm was previously demonstrated (1). This method allows the fabrication of parallel SiNWs network controlled over a large range of doping levels. The resistivity dependence with the P- or N-type in-situ doping level is both related to the nanowires size dependent structural quality and doping specie (2). Feasibility of back gate or top gate N- or P-channel polycrystalline SiNWs TFTs (fig. 1, 2 and 3), and charged chemical species detection (fig. 4) using such TFTs were also demonstrated (3). Our results show the great flexibility in design of planar SiNWs array by direct patterning technique using conventional lithographic tools. The polycristalline silicon NWs make them good candidates for the fabrication of electrically controlled thin film devices (resistors and transistors), in particularly for both chemical sensing and electronics applications. Results show the full compatibility of the nanospacer polycristalline SiNWs technology with the existing silicon CMOS technology, using nanowires as potential sensitive units for integrated gas sensors applications. Indeed, field effect behaviour observed in polycristalline SiNWs based transistors is promising to amplify chemical species detection and for electronics conditioning sensing signal using back gate and top gate configurations respectively. In addition, thanks to silicon surface functionalization possibilities, such results offer a great potential for further developments of integrated SiNWs based (bio)chemical sensors and their implementation in electronic systems.1. F. Demami, L. Pichon, R. Rogel, A. C. Salaun, Mat. Sc. Eng. , 012014 (2009)2. R. Rogel, E. Jacques, L. Pichon, A. C. Salaun, IEEE Trans. Elect. Dev., 61(2), 598-604 (2014)3. A. C. Salaun, L. Pichon, G. Wenga, EUROSENSORS 2014 Procedia Engineering (2014). To be published

Research paper thumbnail of Polysilicon nanowires based field effect transistor compatible with MOS technology for integrated label-free direct detection of DNA hybridization

HAL (Le Centre pour la Communication Scientifique Directe), May 15, 2012

International audienc

Research paper thumbnail of Grounded and suspended polysilicon nanowires for gas sensing applications

HAL (Le Centre pour la Communication Scientifique Directe), Nov 13, 2012

Owing to their physical and electrical properties, silicon nanowires (SiNWs) represent a promisin... more Owing to their physical and electrical properties, silicon nanowires (SiNWs) represent a promising material with strong potential for a large variety of applications. In this study, polycrystalline silicon nanowires (poly-SiNWs) are synthesized using a classical fabrication method commonly used in microelectronic industry: the sidewall spacer formation technique. Assets of this technological process rest on low cost lithographic tools use, classical silicon planar technology compatibility and the possibility to get by direct patterning numerous parallel nanowires with precise location on the substrate. Sidewall spacer formation technique consists in depositing a polysilicon layer by Low Pressure Chemical Vapour Deposition method on a wall patterned by conventional UV lithography technique. Polysilicon film is then etched by anisotropic Reactive Ion Etching (RIE). Accurate control of the etching rate leads to the formation of nanometric size spacers along the vertical sidewall. These spacers are used as polysilicon nanowires. Such synthesis method is performed in three different ways: i) the wall is kept throughout the technological process, so poly-SiNWs are anchored to this wall. ii) the wall is a SiO2 layer deposited by Atmospheric Pressure CVD technique and is removed after nanowires formation. These two configurations lead to the formation of grounded poly-SiNWs. iii) the nanowires underlying sacrificial layer is removed after nanowires synthesis leading to suspended poly-SiNWs. Poly-SiNWs with a curvature radius as low as 50 nm are integrated into the fabrication of resistors and electrical properties are studied in function of N and P type in-situ doping levels over a large range, from 2.1016 at.cm-3 to 2.1020 at.cm-3. Current-temperature measurements performed in the range 200 K - 530 K show that poly-SiNWs dark conductivity is thermally activated following the Mott's theory related to the nanowires size dependent structural quality. Field effect transistors with grounded nanowires as channel region are fabricated and results show potential use of these nanowires for electronic applications. Moreover, from process i) to iii), poly-SiNWs present an increasing surface with environment making them interesting for charged chemical species detection.

Research paper thumbnail of Silicon nanowires based sensors for NH3 detection

HAL (Le Centre pour la Communication Scientifique Directe), Dec 3, 2012

Owing to their physical and electrical properties, semiconducting nanowires are the subject of in... more Owing to their physical and electrical properties, semiconducting nanowires are the subject of intense research activities. In particular, silicon nanowires (SiNWs) are full compatible with the high reliable well known CMOS (Complementary Metal Oxide Semiconductor) silicon technology. In addition, thanks to their high surface to volume ratio, SiNWs are good candidates for fabrication of high sensitive chemical sensors. SiNWs can be prepared by one of two approaches, "top-down" or "bottom up". In a bottom up strategy the individual base elements (atoms, molecules...) of the system are linked together to form larger subsystems. The main drawbacks of these synthesis methods for a 3D integration are the difficulty in control of size and positioning of the nanowires. In this case, nanowires need to be selectively collected and manipulated to be assembled in a planar layout. The "top down" approach starts from bulk materials and scales down the patterned areas. In this way, several advanced lithographic tools with nanometer size resolution rest on the high cost generated, and more generally the low throughput capability is unsuitable with mass production. In this work, undoped silicon nanowires are fabricated following these tow approaches: i) Au-catalyst vapour liquid solid (VLS) SiNWs [1] (bottom-up), and ii) suspended sidewall spacer (SS) polycristalline SiNWs (top down) [2]. SiNWs are integrated into resistors used as gas (ammonia) sensors. Fabrication of two types of SiNWs based devices uses classical silicon microelectronic technologies [3]. Specific design is developed for VLS SiNWs based resistors to be compatible with a mass production planar layout. Fabrication of SS-polySiNWs based devices uses classical lithographic tools. Ammonia molecules adsorbed on the surface of undoped SiNWs act as electron donors (reducing agents) resulting to an increase of the current into the nanowires. Then, ammonia detection is performed by measuring current into SiNWs based resistors. Measurements are carried out at room temperature, in a vacuum chamber, under controlled ammonia/nitrogen (NH3:N2) mixture varying from 2 ppm to 700 ppm. Results highlight that the relative response, Sg, defined as Sg=(I-Ig)/I where I and Ig are the current values for devices in vacuum and reactive ambient respectively, is higher for suspended polycristalline SiNWs based devices, probably related to a high structural defects density. For both sensors, response to ammonia detection follows a linear behaviour for ammonia concentration lower than 350ppm, and relative sensitivity, S=Sg/NH3, is 99.5%/ppm. These results show potential use of these nanowires for charged chemical species detection in a fully compatible silicon CMOS technology. [1] Ni L., Demami F., Rogel R., Salaun A.C., Pichon L., Materials Science and Engineering 6, 012013 (2009). [2] Demami F., Pichon L., Rogel R., Salaun A. C., Materials Science and Engineering 6, 012014 (2009). [3] Demami F., Ni L., Rogel R., Salaun A.C., Pichon L., Sensors and Actuators B: Chemical, 170, 159 (2012)

Research paper thumbnail of Grounded and Suspended Polysilicon Nanowires fabricated by Top Down approach

HAL (Le Centre pour la Communication Scientifique Directe), Apr 9, 2012

Owing to their physical and electrical properties, silicon nanowires (SiNWs) represent a promisin... more Owing to their physical and electrical properties, silicon nanowires (SiNWs) represent a promising material with strong potential for a large variety of applications. In this study, polycrystalline silicon nanowires (poly-SiNWs) are synthesized using a classical fabrication method commonly used in microelectronic industry: the sidewall spacer formation technique. Assets of this technological process rest on low cost lithographic tools use, classical silicon planar technology compatibility and the possibility to get by direct patterning numerous parallel nanowires with precise location on the substrate. Sidewall spacer formation technique consists in depositing a polysilicon layer by Low Pressure Chemical Vapour Deposition method on a wall patterned by conventional UV lithography technique. Polysilicon film is then etched by anisotropic Reactive Ion Etching (RIE). Accurate control of the etching rate leads to the formation of nanometric size spacers along the vertical sidewall. These spacers are used as polysilicon nanowires. Such synthesis method is performed in three different ways: i) the wall is kept throughout the technological process, so poly-SiNWs are anchored to this wall. ii) the wall is a SiO2 layer deposited by Atmospheric Pressure CVD technique and is removed after nanowires formation. These two configurations lead to the formation of grounded poly-SiNWs. iii) the nanowires underlying sacrificial layer is removed after nanowires synthesis leading to suspended poly-SiNWs. Poly-SiNWs with a curvature radius as low as 50 nm are integrated into the fabrication of resistors and electrical properties are studied in function of N and P type in-situ doping levels over a large range, from 2.1016 at.cm-3 to 2.1020 at.cm-3. Current-temperature measurements performed in the range 200 K - 530 K show that poly-SiNWs dark conductivity is thermally activated following the Mott's theory related to the nanowires size dependent structural quality. Field effect transistors with grounded nanowires as channel region are fabricated and results show potential use of these nanowires for electronic applications. Moreover, from process i) to iii), poly-SiNWs present an increasing surface with environment making them interesting for charged chemical species detection.

Research paper thumbnail of Thin film Transistrors on polyimide substrate under high deformations

HAL (Le Centre pour la Communication Scientifique Directe), Feb 25, 2015

International audienc

Research paper thumbnail of High rectifying behavior in Al/Si nanocrystal-embedded SiOxNy/p-Si heterojunctions

Semiconductor Science and Technology, Mar 11, 2011

We examine the electrical properties of MIS devices made of Al/Si nanocrystal-SiO x N y /p-Si. Th... more We examine the electrical properties of MIS devices made of Al/Si nanocrystal-SiO x N y /p-Si. The J-V characteristics of the devices present a high rectifying behavior. Temperature measurements show that the forward current is thermally activated following the thermal diffusion model of carriers. At low reverse bias, the current is governed by thermal emission amplified by the Poole-Frenkel effect of carriers from defects located at the silicon nanocrystals/SiO x N y interfaces, whereas tunnel conduction in silicon oxynitride matrix dominates at high reverse bias. The devices exhibit a rectification ratio >10 4 for the current measured at V = ± 1 V. Study reveals that thermal annealing in forming gas (H 2 /N 2) improves the electrical properties of the devices due to the passivation of defects.

Research paper thumbnail of Front Cover: Electronic and Charge Transport Properties in Bridged versus Unbridged Nanohoops: Role of the Nanohoop Size (Chem. Eur. J. 41/2023)

Chemistry: A European Journal, Jun 14, 2023

Research paper thumbnail of Silicon Nanowires based devices for biological/chemical sensors applications

HAL (Le Centre pour la Communication Scientifique Directe), Jun 4, 2012

International audienc

Research paper thumbnail of Step-gate polysilicon nanowires field effect transistor compatible with CMOS technology for label-free DNA biosensor

Biosensors and Bioelectronics, Feb 1, 2013

Currently, detection of DNA hybridization using fluorescence-based detection technique requires e... more Currently, detection of DNA hybridization using fluorescence-based detection technique requires expensive optical systems and complex bioinformatics tools. Hence, the development of new low cost devices that enable direct and highly sensitive detection stimulates a lot of research efforts. Particularly, devices based on silicon nanowires are emerging as ultrasensitive electrical sensors for the direct detection of biological species thanks to their high surface to volume ratio. In this study, we propose innovative devices using step-gate polycrystalline silicon nanowire FET (poly-Si NW FETs), fabricated with simple and low cost fabrication process, and used as ultrasensitive electronic sensor for DNA hybridization. The poly-SiNWs are synthesized using the sidewall spacer formation technique. The detailed fabrication procedure for a step-gate NWFET sensor is described in this paper. Nocomplementary and complementary DNA sequences were clearly discriminated and detection limit to 1fM range is observed. This first result using this nano-device is promising for the development of low cost and ultrasensitive polysilicon nanowires based DNA sensors compatible with the CMOS technology.

Research paper thumbnail of Bottom-gate and Step-gate Polysilicon Nanowires Field Effect Transistors for Ultrasensitive Label-free Biosensing Application

Procedia Engineering, 2012

Simple and low-cost polycrystalline silicon nanowires field effect transistor (poly-SiNWFET) are ... more Simple and low-cost polycrystalline silicon nanowires field effect transistor (poly-SiNWFET) are fabricated using two different configurations: step-gate and back-gate. The nanowires are synthesized using the sidewall spacer formation technique compatible with the well-known CMOS technology. Probe DNA strands immobilization is performed by the functionalization of poly-SiNWs using APTES and glutaraldehyde. Hybridization phenomenon is detected on electrical characteristics of the poly-SiNWFETs. The first results demonstrate that these devices are promising tools for low-cost, real time and label-free DNA sensing with detection limit at 1fM.

Research paper thumbnail of Au-Catalyst Silicon Nanowires Synthesized by Vapor–Liquid–Solid Technique in a V-Shaped Groove: Application for Gas Sensors

Sensor Letters, Aug 1, 2013

ABSTRACT Au-catalyst Vapor–Liquid–Solid (VLS) silicon nanowires (SiNWs) with high density are syn... more ABSTRACT Au-catalyst Vapor–Liquid–Solid (VLS) silicon nanowires (SiNWs) with high density are synthesized on heavily doped polysilicon islands patterned on both sidewalls of the 〈100〉 oriented silicon substrate V-shaped groove. The resulting SiNWs network permits to interconnect two heavily doped polysilicon islands leading to the formation of a resistor inside the groove. The quantitative dynamic measurements under exposure of this device to a wide range of gas (ammonia) concentration (from 10 ppm to 350 ppm) were carried out and demonstrated the feasibility of highly sensitive SiNWs based resistors used as gas sensors.

Research paper thumbnail of Ammonia Sensors Based on Suspended Silicon Nanowires

Procedia Engineering, 2014

Research paper thumbnail of N‐type <i>in‐situ</i> doping effect on vapour‐liquid‐solid silicon nanowire properties for gas sensing applications

Physica status solidi, Feb 1, 2014

N‐type in‐situ doped SiNWs based resistors are fabricated and used as gas (ammonia) sensors. SiNW... more N‐type in‐situ doped SiNWs based resistors are fabricated and used as gas (ammonia) sensors. SiNWs are prepared by vapour‐liquid‐solid method (VLS) using gold as catalyst. In‐situ doping level is adjusted by varying the phosphine to silane mole ratio. Because SiNWs can act as sensitive units specific design is developed to allow large sensing areas, following a process fabrication compatible with a mass production planar layout. SiNWs doping effect on ammonia detection is carried out under controlled ammonia/nitrogen mixture varying from 2 ppm to 700 ppm. Results highlight that the relative response, Sg=(I0‐Ig)/I0, where I0 and Ig are the current values in vacuum and reactive ambient respectively, follows a linear behaviour. The relative sensitivity, (S=ΔSg/Δ[NH3]) decreases, whereas the sensitivity (SxI0) increases with the increase of the VLS SiNWs doping level. (© 2014 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Research paper thumbnail of Silicon nanowires synthesized by VLS technique in a V-shaped groove for gas sensing applications

HAL (Le Centre pour la Communication Scientifique Directe), May 14, 2012

International audienc

Research paper thumbnail of Fabrication et caractérisation électrique d'un capteur de gaz à base de nanofils de silicium suspendus

HAL (Le Centre pour la Communication Scientifique Directe), Nov 28, 2013

Cet article présente un TP proposé à des étudiants de masters ou filières d'écoles d'ingénieurs r... more Cet article présente un TP proposé à des étudiants de masters ou filières d'écoles d'ingénieurs relevant des nanosciences. Il s'agit de fabriquer en salle blanche un capteur de gaz à base d'un réseau de nanofils de silicium suspendus et de mesurer sa sensibilité à l'ammoniac. Les étudiants sont ainsi initiés à la fois à la fabrication technologique en salle blanche d'un composant, à la caractérisation électrique et structurale ainsi qu'à son application pour la détection de gaz.

Research paper thumbnail of In-situ doping influence on Vapor Liquid Solid Silicon nanowires electrical pRoperties for gas sensing application

HAL (Le Centre pour la Communication Scientifique Directe), May 27, 2013

International audienc

Research paper thumbnail of Silicon nanowires synthesis for chemical and biological sensors applications

HAL (Le Centre pour la Communication Scientifique Directe), Nov 13, 2013

Research paper thumbnail of Nanofils de silicium utilisés dans des capteurs chimiques et biologiques

HAL (Le Centre pour la Communication Scientifique Directe), Oct 3, 2011

Research paper thumbnail of Highly Flexible Microcrystalline Silicon n-Type TFT on PEN Bent to a Curvature Radius of 0.75 mm

IEEE Transactions on Electron Devices, Oct 1, 2015

Electrical and mechanical performances of microcrystalline silicon top-gate thin-film transistors... more Electrical and mechanical performances of microcrystalline silicon top-gate thin-film transistors (TFTs) on flexible substrate under high bending is presented. These devices are directly fabricated on 25-µm-thick Polyethylene naphthalate (PEN) at a maximum temperature of 180°C. Tensile and compressive bending are performed and revealed that the TFTs can hold curvature radii of 1.5 mm without losing their performance and 0.75 mm with lower electrical performances. The limiting factor on the flexibility is shown to be the mechanical behavior of silicon nitride film used as a gate insulator. These extremely high curvatures demonstrate the possibility to use silicon technology in foldable electronics. TFTs are also shown to fully recover their characteristics when reflattened after such very low curvature radii. It opens the way to fold in half an electronic circuit to be stored and reused when reflattened.

Research paper thumbnail of Polycristalline silicon nanowires based TFTs compatible with CMOS technology for chemical integrated sensors

HAL (Le Centre pour la Communication Scientifique Directe), Feb 25, 2015

International audienceThanks to their high surface to volume ratio, silicon nanowires (SiNWs) are... more International audienceThanks to their high surface to volume ratio, silicon nanowires (SiNWs) are good candidates as sensitive units for fabrication of high sensitive chemical sensors. SiNWs can be prepared by one of two approaches, “top-down“ and “bottom up”. In a bottom up strategy synthesis methods most developed are layer-by-layer self-assembly, Vapor Liquid Solid (VLS) and using matrix template. The main drawbacks of these synthesis methods for a 3D integration are the difficulty in control of size and positioning of the nanowires. In this case, nanowires need to be selectively collected and manipulated to be assembled in a planar layout. For the “top down” approach several advanced nanopatterning techniques were developed such as e-beam, atomic force microscopy (AFM), deep UV and nanoimprint lithographies, to obtain SiNWs. The main drawbacks of these advanced lithographic tools with nanometer size resolution rest on the high cost generated, and more generally the low throughput capability unsuitable with mass production. Because SiNWs synthesis can be compatible with the reproducible and reliable performances of the established silicon technology, SiNWs based sensor integration will allow a lower manufacturing cost, in addition to the advantageous electronic features of embedded detection and signal processing in silicon technology. The intrinsic reliability of the well-known semiconductor CMOS (Complementary Metal Oxide Semiconductor) process also guarantees reproducible and reliable performances. In our study, polycrystalline silicon nanowires are synthesized following the top-down approach using a classical fabrication method commonly used in microelectronic industry: the sidewall spacer formation technique. The feasibility of these polycristalline SiNWs with a curvature radius as low as 50 nm was previously demonstrated (1). This method allows the fabrication of parallel SiNWs network controlled over a large range of doping levels. The resistivity dependence with the P- or N-type in-situ doping level is both related to the nanowires size dependent structural quality and doping specie (2). Feasibility of back gate or top gate N- or P-channel polycrystalline SiNWs TFTs (fig. 1, 2 and 3), and charged chemical species detection (fig. 4) using such TFTs were also demonstrated (3). Our results show the great flexibility in design of planar SiNWs array by direct patterning technique using conventional lithographic tools. The polycristalline silicon NWs make them good candidates for the fabrication of electrically controlled thin film devices (resistors and transistors), in particularly for both chemical sensing and electronics applications. Results show the full compatibility of the nanospacer polycristalline SiNWs technology with the existing silicon CMOS technology, using nanowires as potential sensitive units for integrated gas sensors applications. Indeed, field effect behaviour observed in polycristalline SiNWs based transistors is promising to amplify chemical species detection and for electronics conditioning sensing signal using back gate and top gate configurations respectively. In addition, thanks to silicon surface functionalization possibilities, such results offer a great potential for further developments of integrated SiNWs based (bio)chemical sensors and their implementation in electronic systems.1. F. Demami, L. Pichon, R. Rogel, A. C. Salaun, Mat. Sc. Eng. , 012014 (2009)2. R. Rogel, E. Jacques, L. Pichon, A. C. Salaun, IEEE Trans. Elect. Dev., 61(2), 598-604 (2014)3. A. C. Salaun, L. Pichon, G. Wenga, EUROSENSORS 2014 Procedia Engineering (2014). To be published

Research paper thumbnail of Polysilicon nanowires based field effect transistor compatible with MOS technology for integrated label-free direct detection of DNA hybridization

HAL (Le Centre pour la Communication Scientifique Directe), May 15, 2012

International audienc

Research paper thumbnail of Grounded and suspended polysilicon nanowires for gas sensing applications

HAL (Le Centre pour la Communication Scientifique Directe), Nov 13, 2012

Owing to their physical and electrical properties, silicon nanowires (SiNWs) represent a promisin... more Owing to their physical and electrical properties, silicon nanowires (SiNWs) represent a promising material with strong potential for a large variety of applications. In this study, polycrystalline silicon nanowires (poly-SiNWs) are synthesized using a classical fabrication method commonly used in microelectronic industry: the sidewall spacer formation technique. Assets of this technological process rest on low cost lithographic tools use, classical silicon planar technology compatibility and the possibility to get by direct patterning numerous parallel nanowires with precise location on the substrate. Sidewall spacer formation technique consists in depositing a polysilicon layer by Low Pressure Chemical Vapour Deposition method on a wall patterned by conventional UV lithography technique. Polysilicon film is then etched by anisotropic Reactive Ion Etching (RIE). Accurate control of the etching rate leads to the formation of nanometric size spacers along the vertical sidewall. These spacers are used as polysilicon nanowires. Such synthesis method is performed in three different ways: i) the wall is kept throughout the technological process, so poly-SiNWs are anchored to this wall. ii) the wall is a SiO2 layer deposited by Atmospheric Pressure CVD technique and is removed after nanowires formation. These two configurations lead to the formation of grounded poly-SiNWs. iii) the nanowires underlying sacrificial layer is removed after nanowires synthesis leading to suspended poly-SiNWs. Poly-SiNWs with a curvature radius as low as 50 nm are integrated into the fabrication of resistors and electrical properties are studied in function of N and P type in-situ doping levels over a large range, from 2.1016 at.cm-3 to 2.1020 at.cm-3. Current-temperature measurements performed in the range 200 K - 530 K show that poly-SiNWs dark conductivity is thermally activated following the Mott's theory related to the nanowires size dependent structural quality. Field effect transistors with grounded nanowires as channel region are fabricated and results show potential use of these nanowires for electronic applications. Moreover, from process i) to iii), poly-SiNWs present an increasing surface with environment making them interesting for charged chemical species detection.

Research paper thumbnail of Silicon nanowires based sensors for NH3 detection

HAL (Le Centre pour la Communication Scientifique Directe), Dec 3, 2012

Owing to their physical and electrical properties, semiconducting nanowires are the subject of in... more Owing to their physical and electrical properties, semiconducting nanowires are the subject of intense research activities. In particular, silicon nanowires (SiNWs) are full compatible with the high reliable well known CMOS (Complementary Metal Oxide Semiconductor) silicon technology. In addition, thanks to their high surface to volume ratio, SiNWs are good candidates for fabrication of high sensitive chemical sensors. SiNWs can be prepared by one of two approaches, "top-down" or "bottom up". In a bottom up strategy the individual base elements (atoms, molecules...) of the system are linked together to form larger subsystems. The main drawbacks of these synthesis methods for a 3D integration are the difficulty in control of size and positioning of the nanowires. In this case, nanowires need to be selectively collected and manipulated to be assembled in a planar layout. The "top down" approach starts from bulk materials and scales down the patterned areas. In this way, several advanced lithographic tools with nanometer size resolution rest on the high cost generated, and more generally the low throughput capability is unsuitable with mass production. In this work, undoped silicon nanowires are fabricated following these tow approaches: i) Au-catalyst vapour liquid solid (VLS) SiNWs [1] (bottom-up), and ii) suspended sidewall spacer (SS) polycristalline SiNWs (top down) [2]. SiNWs are integrated into resistors used as gas (ammonia) sensors. Fabrication of two types of SiNWs based devices uses classical silicon microelectronic technologies [3]. Specific design is developed for VLS SiNWs based resistors to be compatible with a mass production planar layout. Fabrication of SS-polySiNWs based devices uses classical lithographic tools. Ammonia molecules adsorbed on the surface of undoped SiNWs act as electron donors (reducing agents) resulting to an increase of the current into the nanowires. Then, ammonia detection is performed by measuring current into SiNWs based resistors. Measurements are carried out at room temperature, in a vacuum chamber, under controlled ammonia/nitrogen (NH3:N2) mixture varying from 2 ppm to 700 ppm. Results highlight that the relative response, Sg, defined as Sg=(I-Ig)/I where I and Ig are the current values for devices in vacuum and reactive ambient respectively, is higher for suspended polycristalline SiNWs based devices, probably related to a high structural defects density. For both sensors, response to ammonia detection follows a linear behaviour for ammonia concentration lower than 350ppm, and relative sensitivity, S=Sg/NH3, is 99.5%/ppm. These results show potential use of these nanowires for charged chemical species detection in a fully compatible silicon CMOS technology. [1] Ni L., Demami F., Rogel R., Salaun A.C., Pichon L., Materials Science and Engineering 6, 012013 (2009). [2] Demami F., Pichon L., Rogel R., Salaun A. C., Materials Science and Engineering 6, 012014 (2009). [3] Demami F., Ni L., Rogel R., Salaun A.C., Pichon L., Sensors and Actuators B: Chemical, 170, 159 (2012)

Research paper thumbnail of Grounded and Suspended Polysilicon Nanowires fabricated by Top Down approach

HAL (Le Centre pour la Communication Scientifique Directe), Apr 9, 2012

Owing to their physical and electrical properties, silicon nanowires (SiNWs) represent a promisin... more Owing to their physical and electrical properties, silicon nanowires (SiNWs) represent a promising material with strong potential for a large variety of applications. In this study, polycrystalline silicon nanowires (poly-SiNWs) are synthesized using a classical fabrication method commonly used in microelectronic industry: the sidewall spacer formation technique. Assets of this technological process rest on low cost lithographic tools use, classical silicon planar technology compatibility and the possibility to get by direct patterning numerous parallel nanowires with precise location on the substrate. Sidewall spacer formation technique consists in depositing a polysilicon layer by Low Pressure Chemical Vapour Deposition method on a wall patterned by conventional UV lithography technique. Polysilicon film is then etched by anisotropic Reactive Ion Etching (RIE). Accurate control of the etching rate leads to the formation of nanometric size spacers along the vertical sidewall. These spacers are used as polysilicon nanowires. Such synthesis method is performed in three different ways: i) the wall is kept throughout the technological process, so poly-SiNWs are anchored to this wall. ii) the wall is a SiO2 layer deposited by Atmospheric Pressure CVD technique and is removed after nanowires formation. These two configurations lead to the formation of grounded poly-SiNWs. iii) the nanowires underlying sacrificial layer is removed after nanowires synthesis leading to suspended poly-SiNWs. Poly-SiNWs with a curvature radius as low as 50 nm are integrated into the fabrication of resistors and electrical properties are studied in function of N and P type in-situ doping levels over a large range, from 2.1016 at.cm-3 to 2.1020 at.cm-3. Current-temperature measurements performed in the range 200 K - 530 K show that poly-SiNWs dark conductivity is thermally activated following the Mott's theory related to the nanowires size dependent structural quality. Field effect transistors with grounded nanowires as channel region are fabricated and results show potential use of these nanowires for electronic applications. Moreover, from process i) to iii), poly-SiNWs present an increasing surface with environment making them interesting for charged chemical species detection.

Research paper thumbnail of Thin film Transistrors on polyimide substrate under high deformations

HAL (Le Centre pour la Communication Scientifique Directe), Feb 25, 2015

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