Very low R/sub ON/ measured on 4H-SiC accu-MOSFET high power device

International audienceThis paper describes the I-V characteristics obtained from a 4H-SiC current limiting device. Some specific aspects of the specific on-resistance are discussed in simulation with the DESSIS ISE software. The device behaviors place it in the field of the best Implanted Channel MOSFET (IC-MOSFET) obtained in the literature. The best on-resistance measured is 13 mWcm 2 and the saturation current density reaches 900 Acm-2

OBIC measurements on 1.3 kV 6H-SiC bipolar diodes protected by Junction Lateral Extension

International audienceDue to its good electrical properties, mainly a high critical electric field and a large bandgap, silicon carbide has demonstrated potentialities for high power devices. We have designed and realised bipolar diodes to sustain a reverse voltage of about 1.3 kV. We present below the experimental breakdown voltage we achieved, and results of OBIC measurements

Study of 6H-SiC high voltage bipolar diodes under reverse biases

International audienceSilicon carbide presents electrical properties suitable for many applications especially for high voltage devices. 6H-SiC P+NN+ structures have been fabricated following ISE software simulations in order to block voltages as high as 1.5 kV. In particular, these diodes are realized by surrounding the emitter by a p-type region called junction termination extension (JTE). Electrical characterizations under reverse bias at, room temperature and in various environments (air, silicone oil) show a premature breakdown for the protected diodes. This breakdown is localized at the emitter periphery. Optical beam induced current (OBIC) measurements show a peak of photocurrent at the junction edge, indicating the presence of a high electric field. These results show a protection efficiency of 60% of the JTE. An electrical activation of the aluminum dopants implanted in the JTE around 30% is derived from the analysis of the presented results

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

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Avalanche Diodes with Low Temperature Dependence in 4H-SiC Suitable for Parallel Protection

International audienceAvalanche 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)

Characterization of a 4H-SiC High Power Density Controlled Current Limiter

International audienceMost of silicon devices such as Schottky diode, MOSFET, MESFET have been realized in SiC and show good electrical and thermal characteristics [1]. Considering fault current limiters for serial protection, a lot of structures exists [2, 3], from conventional fuses to other complex systems such as circuit breakers, mechanical switches. Up to now, few specific SiC-current limiter were described [4, 5]. This paper presents experimental characterization of a bi-directional current limiter structure based on a vertical SiC VJFET

On-the-fly Appearance Quantization on GPU for 3D Broadcasting

International audienceThis paper presents an improved client-server system that increases the availability of remote 3D data. In order to reduce the required bandwidth, the data related to the appearance (color and normal) involved in the rendering of meshes and point clouds is quantized on-the-fly during the transmission to the final client, without reducing the geometric complexity. Our new quantization technique for the appearance that can be implemented on the GPU, strongly reduces the CPU load on the server-side and the transmission time is largely decreased

Characterization of a 4H-SiC High Power Density Controlled Current Limiter

International audienceCritical steps for the fabrication of SiC devices are thermal annealing and metal ohmic contact formation. Metal annealing effect on the electrical characteristics of the current limiter underlines the necessity to control this device fabrication step. Measurements of contact resistivity as a function of temperature demonstrate the stability of the N type Ni/SiC contact in the range of 175 K-450 K as its value remains constant around 40 µΩ.cm 2. Post implantation annealing effect on the sheet resistance (Rsh) shows that a 1700°C/30 min annealing gives better trade off in terms of dopant activation and surface roughness. High power density has been measured up to 600 V. Current thermal stability has been measured for an applied drain to source voltage of 100 V and exhibits high power density capabilities of SiC VJFET as a controlled current limiter. Introduction

Silicon Carbide Controlled Current Limiter, Current Limitation Strategies, Foreseen Applications and Benefits

International audienceThe expansion of electricity networks (distribution of energy, telecommunication), strongly contributed to increase the risks of appearance of defects, such as surge or overload. This multiplicity and complexity of electric networks, the need to have reliable systems favoured the development of serial protection devices. Fuse solution allows an efficient and total protection but requires to replace an element in case of failure. Therefore, other solutions have been investigated. Complex systems have been developed, all based on serial compensation, such as supra-conductor material, GTO MOV combination ... Indeed, because of the strong energy appearance during a short circuit, it is necessary to limit and to dissipate the energy of the short circuit, under high bias. This constraint leads to a feasibility study of a current limiter in 4H silicon carbide (4H-SiC). A VJFET structure was retained focusing on a nominal current of IN = 1 A and a nominal voltage of VN = 690 V. The device was optimised, taking into account SiC excellent physical properties. The VJFET was designed checking the trade-off between a low on-resistance value, high voltage capability and the highest gate transconductance value. A first batch of component was made, validating the bi-directional limitation function in both current and voltage mode, (VMAX = 970 V). The efficiency of the protection was validated, demonstrating the capacity of a component to react very quickly (t < 1 µs). Using such a device is very suitable in several applications (protection against short circuit, transient over current…) as it will allow to reduce transient phenomena and thus increase the efficiency and lifetime of the whole system