Dominique Tournier

This paper presents micro-OBIC measurements performed at different voltages on two devices protected by narrow field rings. At the surface of the device #1, a polyimide layer was deposited during the fabrication process. On the contrary, passivation layer was removed on device #2. Thanks to the micro-OBIC micrometer spatial resolution and the spot...

This paper presents the start development of a design-kit for an innovative technology based on the same lateral topology and the same substrate, which is a dual-gate SiC MESFET. From the electrical characteristic of an initial dual-gate MESFETs, a SPICE model of this device has been established. This model allows developing by simulations a design...

This paper presents a study of the Schottky barrier evolution on SBD and JBS diodes over a wide range of temperatures from 80 to 500 K. We show that inhomogeneities of the Schottky contact have a strong impact on the dependence of barrier characteristics with temperature, especially below 200 K. Analysis of the reverse bias current of such diodes a...

SiC MOSFET are now commercially available and show promising performances when considering static losses, commutations and long term reliability. The devices may face short-circuit conditions and knowing their capibility in terms of critical time and repetitive fault is mandatory before integration in commercial systems. This paper presents the sho...

The static characteristics and short-circuit capabilities of SIT (Static Induction Transistor) depend strongly on its channel design. Analysis show that the doping concentration and the width of the channel are crucial parameters in determining the specific on-resistance, threshold voltage and saturation capabilities of the device. Classically SIT...

An ultrafast I-V measurement technique has been developed to measure simultaneously C-V and leakage parameters of SiC power devices. After considering the coupled contribution of both static (leakage current) and dynamic (capacitive current) aspects with respect to high dV/dt voltage ramps, a time-based characterization is detailed and validated on...

This work presents the impact analysis of physical and geometrical parameters on the on-resistance and the breakdown voltage in order to optimize a 600 V pseudo-vertical GaN/Si Schottky rectifier. The results by finite element simulations indicate that the most influent parameter on the resistance is the thickness of the n+ layer. Regarding reverse...

Wide band gap semiconductors are more and more used, especially to design high voltage devices. However, some devices show lower breakdown voltages than those predicted in theory. These early breakdown are in general due to imperfections in the peripheral protections of the active junction. The aim of these protections is to reduce electric field p...

Reliability studies are required for SiC device development. In a previous work we studied the intrinsic ESD robustness of a SiC MESFET. The failure mechanism was related to the triggering of an NPN parasitic transistor. In this work, a new MESFET layout is considered, which optionally include a Zener diode for internal protection. TLP testing and...

Fuses and Circuit Breakers play an important safety role in electrical distribution systems. New challenging applications, especially in DC applications, have brought conventional current limiting devices to their limits. Indeed, mechanical circuit breakers may be too slow to open for novel DC networks with large DC fault current. As well, fuses ma...

Thanks to its structure solely based on semiconductor junctions, JFET allows to fully benefit from Silicon Carbide properties. The very low on-resistance (RON,SP) and higher temperature capability of normally-on devices, make them an attractive choice for high voltage applications such as energy conversion in harsh environment and solid-state break...

This paper presents our study of SiC MOSFETs, JFETs and BJT under capacitive load short-circuit up to 600V. BJTs show heterogeneous results due to unstable technology. In the contrary MOSFETs critical short circuit show bus voltage dependency with critical time of about 10µs at 600V. The failure is repetitive and characterized by a gate to source s...

Trenched-implanted-gate 4H–SiC vertical-channel JFET (TI-VJFET) have been fabricated with self-aligned nickel silicide source and gate contacts using a process sequence that greatly reduces process complexity as it includes only four lithography steps. The effect of the channel geometry on the electrical characteristics has been studied by varying...

This paper deals with the geometry of a high voltage (1200 V) vertical JFET made with 4H silicon carbide, inspired by SIT or commercial solutions like Semisouth's one (principle exposed in Fig. 1). A first layout was designed allowing an easy integration of a free-wheeling diode. Indeed with the maturity of SiC JFET fabrication process, nowadays' t...

In many power electronic inverters, the gate drive failure may put the switch normally-on in short-circuit (SC) risk. The high power density generated thus leads rapidly to the transistor failure. This paper presents our study via electro-thermal simulation of a 1200 V JFET under short circuit. It provides deep insight of physical phenomena present...

The aim of this study consists in comparing effects of temperature on various Silicon Carbide power devices. Static and dynamic electrical characteristics have been measured for temperatures from 80K to 525K.

This work reports on the fabrication and electrical characterization of 3 different diodes. The first one is a Schottky diode with a single 50 µm P+ ring between the edge termination and the active area. The two other diodes are JBS with a 3 µm P+ strips separated by 4 µm and 8 µm respectively. The breakdown voltage ranges from 2.7kV up to 3.7kV de...

The development of high voltage devices is a great challenge. At least, railway and smart grids are examples of applications requiring high voltage devices. SiC power devices and technology seem to be mature enough to give a short term solution. Indeed, silicon carbide devices appear to be the semiconductor of choice for high voltage (> 6.5 kV) app...

Efficient energy management become more and more crucial with increasing energy resource scarcity. Power electronic will play a major role in this field and thus require innovations like using wide band gap semiconductor to build power devices. SiC, GaN, diamond material-based devices are currently more or less mature and will sooner or later requi...

Ce travail de recherche propose une approche nouvelle de modélisation de diodes Schottky/JBS en carbure de silicium en employant la seule équation de Shockley comme terme générique d’un modèle électrique multi-branches. La fonction de Lambert est utilisée pour s’affranchir du caractère implicite de cette équation. In fine, des paramètres - dits phé...

p>Le but de cette étude consiste à comparer les effets de la température sur différents transistors de puissance en SiC (MOSFET, JFET, BJT). Leurs caractéristiques ont été mesurées pour des températures de 80K à 525K. Tous les composants sont fonctionnels à haute température et ont des caractéristiques supérieures aux composants conventionnels en S...

p>Cet article présente la conception d'un thyristor SiC et les résultats de simulation par éléments finis. Ce travail vise à étudier expérimentalement le comportement dynamique d'un thyristor SiC avec gâchette amplificatrice. Ce type de thyristor n'a pas été étudié pour l'instant en détail pour le SiC. Pourtant, avec l'amélioration constante de la...

p>L'usage des semi-conducteurs à large bande interdite est en train de se répandre, notamment pour la réalisation de composants à haute tension. Cependant, certains composants montrent des claquages pour des tensions inférieures aux tensions théoriques prévues. Ces claquages prématurés sont en général liés à l'imperfection des protections périphéri...

Due to our demonstrated stable Tungsten-Schottky barrier at elevated temperatures, and also thanks to our technological process maturity regarding SiC-Schottky contact fabrication, we have implemented the digital logic gates library adopting a normally-on MESFET topology. In this paper we present new experimental results showing the thermal behavio...

Lorsque l’apprentissage par projet couvre plusieurs thématiques, il apparaît que les étudiants sont d’autant plus sensibles à la qualité des ressources mises à disposition et à leur disponibilité. L’évaluation des étudiants est contrastée entre leur plébiscite du contenu de la formation et leur critique des ressources. L’accès à distance à de telle...

Pub. No.: WO/2014/037628 International Application No.: PCT/FR2012/051983 - Publication Date: 13.03.2014 International Filing Date: 05.09.2012

Using a pulsed green laser with a wavelength of 532 nm, a duration pulse of ∼1 ns, and a mean power varying between 1 and 100 mW, induced photocurrents have been measured in 4H-SiC bipolar diodes. Considering the photon energy (2.33 eV) and the bandgap of 4H-SiC (3.2 eV), the generation of electron-hole pair by the conventional single photon absorp...

To address safety issue of DC networks in distribution and generation plants, a specific Current Limiting FET has been design. The fabricated power switch is able to operate in both forward and reverse conduction mode. Short-circuit time to failure has been adjust and a current sensing electrode as been added to ease the monitoring and the drive of...

The aim of this study consists in comparing the effects of temperature on various SiC power devices. Electrical characteristics have been measured for temperatures from 100K to 525K. All devices are suitable for high temperature. However, SiC MOSFETs are not a good choice for cryogenic temperature, while SiC BJTs are less affected by temperature th...

The present study reports the fabrication of localized p-doped silicon carbide zones on 4H-SiC substrate. Selective epitaxial growth of p-doped SiC was performed using the vapour-liquid-solid transport in Al-Si liquid phase. Focus was made on the understanding of the mechanism involved during such growth. It was shown that despite the need of start...

SiC devices become more and more prominent in the power semiconductor industry. Thanks to a technology that seems to be mature enough, SiC devices are becoming more and more sophisticated. Therefore, they can be serious competitors to existing silicon devices in not so distant future at least for high temperature and high power applications. In add...

Turning off a SiC VJFET from INFINEON requires to apply a gate-to-source voltage comprised between the JFET gate threshold voltage and the punch-through voltage. Unfortunately, for applications operating over a large temperature range, these two limits vary with the temperature and reduce the useful blocking gate-to-source voltage range as the temp...

More electric aircraft require converters that can operate over a wide temperature range (-55 to more than 200°C). Silicon carbide JFETs can satisfy these requirements, but there is a need for suitable peripheral components (gate drivers, passives...). In this paper, we present a "smart power module" based on SiC JFETs and dedicated integrated gate...

This works deals with the localized growth of SiC on monocrystalline (100) diamond surface. It describes an attempt of selective epitaxy using vapor–liquid–solid (VLS) transport. Patterns of Al–Si stacking were melted and fed by propane. Morphology, structure and doping type of the SiC deposit were evaluated. The deposit was found to be successfull...

The development of high voltage devices is a great challenge. At least, railway and high voltage distribution network are example of applications requiring high voltage devices. SiC power devices and technology seems to be mature enough to give a short term solution. Indeed, silicon carbide devices appear to be the semiconductor of choice for high...

Également publié en tant que : FR 2975530 (B1) EP 2647051 (A1) WO 2012072751 (A1)

This work deals with the study of the Selective Epitaxial Growth (SEG) of SiC using the Vapour-Liquid-Solid (VLS) transport on diamond (100) substrate with Al-Si as the liquid phase fed by propane. Morphology, structure and doping type of the SiC deposit were determined. Polycrystalline p-doped 3C-SiC was obtained during the growth. Study of the in...

This work deals with the study of the Selective Epitaxial Growth (SEG) of SiC using Vapour-Liquid-Solid (VLS) transport at temperature <= 1100 degrees C. Focus was made on the nucleation step by observing the evolution of the growth as a function of growth duration with variable Si-content of the Al-Si liquid phase. Addition of propane during the i...

This paper presents the methodology for the design of a novel 4H-SiC JFET structure able to sustain 3.3 kV. Comparisons between simulation and characterization res will be made. Taken into account the process limitation, we will also discuss the critical steps and their impact on the electrical characteristics. A design methodology based on Baliga'...

The aim of this study consists in investigating the effects of electrical and thermal stresses on SiC n-p-n bipolar junction transistors (BJTs). The stability of the electrical characteristics of BJTs is inspected under switching operation, DC operation, temperature cycling and continuous thermal stress up to 225°C. While switching operation and te...

Également publié en tant que : FR 2975530 (B1) EP 2647051 (A1) WO 2012072751 (A1)

Également publié en tant que : FR 2975542 (B1) EP 2647053 (A1) WO 2012072759 (A1)

ENGLISH The society evolutions (mastery of energy expenditure and domotisation) lead to development of alternatives to silicon semicondutor technology, and this to answer the increasing requirements at the level applications, both in the domains of the high voltage and the high temperatures. Indeed, the performances of silicon devices reached their...

Selective epitaxial growth in buried patterns was studied using the vapour-liquid-solid mechanism in Al-Si melt in order to obtain p+-doped SiC localized layers on 4H-SiC substrate. Homogeneous deposition with step bunched morphology was obtained by adding propane at room temperature before growth at 1100 degrees C. Patterns as large as 800 pm and...

4H-SiC vertical bipolar power diodes have been fabricated with bilayer metallic anode contact based on an Al-Ti-Ni ohmic contact and a thick Al over-metallization. An optical window of 100 x 100 mu m(2) has been created through the anode contact with a SIMS Cameca IMS 4F equipment using Cs+ primary ions at 10 kV and with a beam spot size of 500 nm....

Optical Beam Induced Current (OBIC) measurements have been performed on 4H-SiC avalanche diodes with a very thin and highly doped avalanche region. The light source used in this study is an Ar-laser with a wavelength of 351 nm which results in a mixed carrier injection. From these measurements, impact ionization coefficients for 4H-SiC have been ex...

Silicon Carbide VDMOS with integrated current and temperature sensors have been successfully fabricated without degradation of the chip forward or reverse characteristics due to the sensors. The temperature sensors show impedance correlated to the temperature, which permits to track the drift region's temperature of the device. We have shown that t...

In this work we report on SiC epitaxial growth by vapour-liquid-solid (VLS) mechanism on on-axis 4H-SiC(0001) substrates which were previously patterned to form mesa structures. The liquid phase was set to Al70Si30. At 1100 degrees C, it led to very high homoepitaxial lateral growth (140 pm/h) with pronounced spiral growth and in plane anisotropy o...

AMPERE laboratory (Lyon, France) and Center National Microelectronics of Barcelona (SPAIN) have recently developed lateral MESFETs in SiC. The current purpose is to develop electronic systems based on these MESFETs for applications operating in harsh environments (e.g. High Temperature > 300 deg C). This paper presents the design of an integrated p...

This work reports of investigation on the origin of the ohmic behavior for Ti/Al based contacts on n-GaN. Indeed, last publications tend to prove that the "nitrogen vacancy" theory is not confirmed by the experimental ground available. To find new answers, we first made electrical characterizations on some Al/Ti/n(+)-GaN contacts with different ann...

In this work we report on the study of twin boundary (TB) evolution during heteroepitaxial growth of 3C-SiC on patterned 4H-SiC(0001) substrate by vapour-liquid-solid (VLS) mechanism. Ge50Si50 melt was used at a temperature of 1450 degrees C. 3C-SiC deposit was obtained on top and outside the mesas. Some lateral enlargement of these mesas was obser...

Since a few years, VLS transport is studied not only for homoepitaxial SiC growth but also for SiC selective epitaxial growth (SEG). In this approach, a stacking of silicon and aluminum layers is deposited on the substrate and patterns are created by photolithography. Upon melting, the Al-Si liquid droplets are fed by propane to obtain the SEG of p...

Power electronics based on wide band gap materials, such as silicon carbide (SiC) or gallium nitride (GaN), are nowadays capable of operation at increased ambient temperatures. High Temperature Intelligent Power Modules are unfortunately not available due to a lack of integrated driver able to withstand either harsh environment or enhanced junction...

A multi-physics model of the VJFET with a lateral channel is presented. The model has been implemented and tested in SABER using the MAST language. The model includes an asymmetric representation of the lateral channel which is the main contribution of the paper. The blocking condition is not so obvious and it is presented in details. Each junction...

Progress in semiconductor technologies have been so consequent these last years that theoretical limits of silicon, specifically in the field of high power, high voltage and high temperature have been achieved. At the same time, research on other semiconductors, and especially wide bandgap semiconductors have allowed to fabricate various power devi...

In this work, we report on the use of patterned 4H–SiC(0001) substrates for the heteroepitaxial growth of 3C–SiC by vapor–liquid–solid (VLS) mechanism using Ge50Si50 melt. Mesas structures of various size and shape were obtained by standard photolithography and dry etching processes. On the temperature range investigated 1300–1450 °C, 3C–SiC deposi...

Higher temperature electronics is driving large development efforts regarding many issues, especially t h e o b j e c t i v e o f i n t e g r a t i o n. T h e m a i n targets for a higher level of integration come with the constraint of increased reliability. At converter level, these objectives face many challenges and 3 of them are discussed here...

4H-SiC p+-n diodes with very low reverse current and hard avalanche breakdown voltage were fabricated. Optical beam induced current (OBIC) measurements were employed to determine the impact ionization coefficients of electrons and holes. Simulations performed using the extracted values and the comparison of these coefficients with published data ar...

Avalanche diodes have been fabricated on 4H-SiC substrate. These diodes show an abrupt avalanche voltage of about 59 V which corresponds to the calculated theoretical one using our previously determined impact ionization coefficients. This avalanche voltage increases by as small as 3.7 mV/K over the investigated temperature range (150K-420K).

In this work we report on 3C-SiC heteroepitaxial growth on 4H-SiC(0001) substrates which were patterned to form mesa structures. Two different deposition techniques were used and compared: vapour-liquid-solid (VLS) mechanism and chemical vapour deposition (CVD). The results in terms of surface morphology evolution and the polytype formation using t...

High temperature power electronics has become possible with the recent availability of silicon carbide devices. This material, as other wide-bandgap semiconductors, can operate at temperatures above 500°C, whereas silicon is limited to 150-200°C. Applications such as transportation or deep oil and gas wells drilling can benefit. A few converters op...

In this paper, we investigate the weighted H_∞ Luenberger observation and the weighted H8 filtering. The motivation is the design of signal differentiators. The standard Luenberger observer structure is modified in order to formulate the design problem as a convex optimization problem involving Linear Matrix Inequality (LMI) constraints....

In this paper we review different differentiation methods and we investigate their digital implementation. The motivation is the design of a numerical differentiator based on a low-cost microcontroller device. Standard digital differentiation algorithms are presented and an alternative approach based on weighted H∞ filtering is introduced. In this...

L'essor qu'ont connu les matériaux à grand gap comme le carbure de silicium (SiC) ou le nitrite de gallium (GaN), a permis le développement de composants de puissance qualifiés pour la haute température. Mais pour concevoir des modules de puissance intelligents destinés aux environnements extrêmes, il est nécessaire de développer un circuit de comm...