VTH subthreshold hysteresis technology and temperature dependence in commercial 4H-SiC MOSFETs

VTH subthreshold hysteresis measured in commercially available 4H-SiC MOSFET is more pronounced in trench than in planar ones. All planar devices from different manufacturers exhibit an inverse temperature dependence, with the hysteresis amplitude reducing as the temperature increases, whereas all trench devices from different manufacturers exhibit the opposite behaviour. A physical interpretation is proposed, based on experimental evidence, which demonstrates that temperature dependence of the VTH subthreshold hysteresis is related to the technology. The findings are relevant to the ongoing discussion on SiC bespoke validation standards development and contribute important new insight

Effects of the laser beam size on the Optical Beam Induced Current (OBIC) for the study of Wide Band Gap (WBG) Semi-Conductor Devices

International audienceUV Laser is used to generate electron-hole pairs into Wide Band-Gap (WBG) semiconductors (SiC, GaN or Ga2O3). In the space charge region, the electric field drives the collected carriers and a current, so-called Optical Beam induced Current (OBIC), can be measured. The induced current is then directly related to the electrical field in the device. The OBIC, is a non-destructive technique, which has been previously successfully used to characterize High Voltage (HV) SiC devices [1, 2, 3, 4]. In order to fully benefit of the advantages provided by WBG semiconductors materials and to avoid premature breakdown of the high voltage devices, it is mandatory to have efficient peripheral protections such as a MESA, a JTE and JTE rings…The OBIC characterization can help the technology computer-aided design (TCAD) and the device process to optimize the efficiency of the periphery protection by analyzing the electric field distribution in the structure and especially at the junction periphery. In this talk, we will present an in-house testbench called micro-OBIC which will allow us to characterize HV PiN diodes with a micro-meter spatial resolution

V TH -Hysteresis and Interface States Characterisation in SiC Power MOSFETs with Planar and Trench Gate

International audienceThis paper contributes to investigations on the threshold-voltage (VTH) hysteresis in SiC power MOSFETs. Such effect is of relevance mainly for sub-threshold operation of the devices, but needs to be told apart from stress-related VTH-drift phenomena for technology maturity and reliability validation goals. Important differences exist in commercially available devices, particularly in relation to their gate technology, planar or trench, the latter also showing a marked temperature dependence of the hysteretic range. Based on the experimental characterization of the interface capacitance and charge, this paper puts forward a methodology for determining the types of traps affecting the various devices, with the aim of contributing a tool to assist driving of technological maturity in future generation devices. This paper also shows the potential of capacitance hysteresis measurement to the estimation of the distribution of interface

Near breakdown voltage optical beam induced current (OBIC) on 4H-SiC bipolar diode

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Characterisation and modelling of 4H-SiC Schottky and JBS diode for high voltage applications

La diode Schottky SiC est un composant qui peut potentiellement remplacer la diode PiN Si dans les applications de puissance. Effectivement, la tenue en tension élevée, la faible résistivité, ainsi que l’indépendance de la température du courant de recouvrement rendent cette diode idéale pour les convertis- seurs de puissance DC/DC. Cependant, face à l’abondance des composants Si sur le marché, la diode Schottky rencontre une certaine réticence. Malgré les nombreuses démonstrations de systèmes électroniques de puissance réalisés, la fiabilité de cette technologie n’arrive pas à convaincre. Cette étude porte sur la caractérisation en régime statique sur une large gamme de températures et l’évaluation de la fiabilité en surcharge des diodes Schottky et JBS SiC-4H. La caractérisation en température a permis de proposer des modèles de la carac- téristique directe et inverse sur une gamme étendue de températures. Les tests en surcharge ont permis de comparer la fiabilité de diodes expérimentales et commerciales à fin de montrer la maturité de cette technologie.The SiC Schottky diode can potentially replace the PiN diode in power appli- cations. As a matter of fact, high blocking voltage, low resistivity as well as temperature independence of the reverse recovery current make this diode ideal for DC/DC power converters. Nevertheless, Schottky diodes meet some reluc- tance before the abundance of PiN Si diodes. Despite the numerous demons- trations of power electronics systems, there are still some reliability aspects to improve. This study focuses on static characteristic in a large temperature range and reliability assessment of repetitive surge test of Schottky and JBS diodes. The measurements of forward and reverse characteristics yielded new models in a wide temperature range. Repetitive surge tests enabled us to com- pare the reliability of experimental and commercial diodes in order to prove the maturity of this technology

Caractérisation et modélisation de diodes Schottky et JBS SiC-4H pour des applications haute tension

The SiC Schottky diode can potentially replace the PiN diode in power appli- cations. As a matter of fact, high blocking voltage, low resistivity as well as temperature independence of the reverse recovery current make this diode ideal for DC/DC power converters. Nevertheless, Schottky diodes meet some reluc- tance before the abundance of PiN Si diodes. Despite the numerous demons- trations of power electronics systems, there are still some reliability aspects to improve. This study focuses on static characteristic in a large temperature range and reliability assessment of repetitive surge test of Schottky and JBS diodes. The measurements of forward and reverse characteristics yielded new models in a wide temperature range. Repetitive surge tests enabled us to com- pare the reliability of experimental and commercial diodes in order to prove the maturity of this technology.La diode Schottky SiC est un composant qui peut potentiellement remplacer la diode PiN Si dans les applications de puissance. Effectivement, la tenue en tension élevée, la faible résistivité, ainsi que l’indépendance de la température du courant de recouvrement rendent cette diode idéale pour les convertis- seurs de puissance DC/DC. Cependant, face à l’abondance des composants Si sur le marché, la diode Schottky rencontre une certaine réticence. Malgré les nombreuses démonstrations de systèmes électroniques de puissance réalisés, la fiabilité de cette technologie n’arrive pas à convaincre. Cette étude porte sur la caractérisation en régime statique sur une large gamme de températures et l’évaluation de la fiabilité en surcharge des diodes Schottky et JBS SiC-4H. La caractérisation en température a permis de proposer des modèles de la carac- téristique directe et inverse sur une gamme étendue de températures. Les tests en surcharge ont permis de comparer la fiabilité de diodes expérimentales et commerciales à fin de montrer la maturité de cette technologie

Static characteristics of 5 kV SiC BJTs and Darlington’s

International audienceHigh voltage low current SiC BJT transistors are interesting devices for applications like active filters, current limiters and active snubbers where high voltage blocking capabilities are required. Few attempts[1]–[3] have proved that such devices can be manufactured and fulfill the requirements in terms of breakdown voltage, beta and reliability. SuperGrid Institute has designed 10 kV - 5A SiC BJTs as a proof of concept with the aim to increase the nominal current rating to 50 A. This devices are intended to operate in the abovementioned applications and also to be employed as a power switch in HVDC converters. This abstract evaluates the static performances of the first run of 10 kV – 5 A BJTs from SuperGrid. The switching performance will be assessed and reported in the full paper

Cryogenic to High Temperature Exploration of 4H-SiC W-SBD

International audienceW-SBD show exceptional reliability from 200 to 500K, however, its barrier analysis has never been performed thoroughly down 81K. This paper shows our study of Schottky barrier and Richardson coefficient was extracted for different temperature ranges. We observed fluctuation in function of the temperature. We analyse this phenomenon and compare it to literature for other barriers. Measurements of reverse characteristics up 1200V have been performed from 81 to 450K. It confirms that partial ionization influence on the drift doping impacts on the barrier height

Subthreshold Drain current hysteresis of planar SiC MOSFETs

International audienceVTH instabilities of SiC MOSFET are made of a permanent and a recoverable part. VTH hysteresis is a recoverable instability which affects the operation of the device since the threshold voltage depends on the negative bias applied previously, but is erased when the MOSFET is biased above the threshold voltage. In this paper, the phenomenon is assessed through experiments and TCAD simulation. The results are in good agreement and show that the VTH hysteresis is mainly caused by the hole trapping in the oxide near the interface. The C(V) characteristics of the measured device is similar to the simulated device having a concentration of 10e12 holes/cm2 trapped at the interface

Demonstration of the Short-circuit Ruggedness of a 10 kV Silicon Carbide Bipolar Junction Transistor

International audienceStatic, switching and short-circuit characterization of a 10 kV-class Silicon Carbide (SiC) Bipolar Junction Transistor (BJT) is reported. The 2.4 mm² SiC BJT show good static and switching behavior. The current gain is low compared to literature, but several issues have been identified and can beimproved. For the first time, the Short-circuit ruggedness of a 10 kV SiC-BJT is reported. These tests show outstanding performance with at least 16 μs withstand time. Several samples have been brought to failure and revealed an outstanding 52.1 J/cm2 of short-circuit critical energy at 32% of breakdown voltage. The failure seems to happen on the top face metallization since the devices failed in blocked mode and the base-emitter terminals shorted. The SiC BJT handles without failing at least 3 times the critical Short-circuit energy of the commercial SiC MOSFETs. In addition, switching performance is much better than that of Si-IGBTs