Papers by Keyword: Junction Barrier Schottky (JBS) Diode

Abstract: The performance of Junction Barrier Schottky (JBS) diodes developed for medium voltage hard-switched Naval power conversion is reported. Nominally 60 A, 4.5kV rated JBS freewheeling diodes were paired with similarly rated Si IGBTs and evaluated for temperature dependent static and dynamic characteristics as well as HTRB and surge capability. The SiC JBS/Si IGBT pair was also directly compared to Si PiN diode/Si IGBT with similar ratings. Compared to Si, the SiC freewheeling diode produced over twenty times lower reverse recovery charge leading to approximately a factor-of-four-reduction in turn-on loss. Alternatively, for equivalent total switching loss, the SiC JBS/Si IGBT hybrid configuration allows for at least a 50% increase in specific switched power density. Reliability testing showed the devices to be robust with zero failures.

Abstract: This paper presents the high blocking capability of the 4H-SiC tungsten Schottky and junction barrier Schottky (JBS) diodes at room temperature as well as at high operating temperature. First, we present the design of the proposed devices and the process employed for their fabrication. In a second part, their forward and reverse characteristics at room temperature will be presented. Our rectifiers exhibit blocking capability up to 9kV at room temperature. Then, we investigate the reverse current behaviour at 5kV from room temperature to 250°C under vacuum. JBS and Schottky devices that are capable to block 8kV at room temperature, show leakage current inferior to 100µA at 250°C when reverse biased at 5kV. It confirms the capability of Silicon Carbide to produce devices capable of operation at temperatures and voltages above the Silicon limits.

Abstract: 600V-30A 4H-SiC Junction Barrier Schottky（JBS）diodes were designed and fabricated using SiC epitaxy and device technology. SiC JBS diodes were packaged in Si IGBT module，and switching measurements were done at 125°C. As free-wheeling diode for Si IGBT, 600V SiC JBS diode was compared to 600V ultra-fast diode from International Rectifier. SiC diode achieved 90% recovery loss reduction and corresponding IGBT showed 30% lower turn-on loss. However, SiC JBS diode has larger on-state voltage drop due to small chip area. On-state power loss will be lowered by increasing SiC chip area.

Abstract: The impacts of threading dislocations, surface defects, donor concentration, and schottky Schottky barrier height on the reverse IV characteristic of silicon carbide (SiC) junction barrier schottky Schottky (JBS) diodes were investigated. The 100 A JBS diodes were fabricated on 4H-SiC 3-inch N-type wafers with two types of threading dislocation density. The typical densities are were 0.2×104 and 3.8×104 cm-2, respectively. The improvement of vIt was found that variations in the leakage current and the high yield of large area JBS diodes werecould be were obtained improved by using a wafer with a low threading dislocation density. In the range of low leakage current, the investigation shows showed a correlation between leakage current and threading dislocation density.

Abstract: In this work we studied different Schottky contacts to 4H-SiC with the aim to obtain Schottky Barrier diodes (SBDs) and Junction Barrier Schottky diodes (JBS) able to operate at high temperatures, frequencies and power densities with low power losses. Schottky contacts were fabricated using Mo and Mo/Al layers annealed up to 600 °C using a Rapid Thermal Process (RTP). A comparison with previous results obtained with Ni, Ti and Ti/Al layers annealed up to 400 °C is also proposed. The Schottky contacts were characterized by means of standard Current-Voltage (I-V) and Capacitance-Voltage (C-V) techniques. X-ray Photoelectron Spectroscopy (XPS) analyses were performed in depth profile mode in order to study the structural evolution of the interface Mo/SiC and Al/Mo during annealing treatments. Mo/Al contacts show a lower barrier height and better overall performances in forward polarization when compared to the Ti- and Ni-based contacts, and they are very promising for Schottky contact fabrication on SBD and JBS.

Abstract: In the present paper, 4H-SiC JBS diodes with "boron" p–n junctions have been investigated by means of deep-level transient spectroscopy (DLTS). The sign of the DLTS signal for all the 4H-SiC diodes under study, was positive. The "anomaly" of the DLTS spectra measured is apparently connected with the properties of "boron" p–n junctions. In particular, is presented the role of deep D-centers in recompensation of donors in the JBS diodes.

Abstract: Of all the wide bandgap semiconductors, SiC is currently the most attractive material for aerospace applications. It offers significant advantages at high temperatures and high voltage levels while benefiting from an excellent thermal conductivity, the resistance to a harsh radiation environment (in particular in medium low orbits (MEO) where the Van Allan belts show a high concentration of electron and proton radiation) and an advanced materials technology. Due to the significant progress in the last years in monocrystalline SiC material fabrication and process technology, the space industry is increasingly interested in exploiting the SiC characteristics for electronic application. Although the requirement for space components are highly demanding with space qualified technological processes required, it is expected that high quality commercial SiC components submitted to a stringent screening process will allow the realisation of highly reliable space components. Electronic applications of monocrystalline SiC for space mainly exploit the high breakdown electric field which allows for lower specific on-resistances due to high doping and thinner drift region layers in vertical SiC power device structures. Among all SiC power devices, high voltage rectifiers have reached the highest degree of maturity. EADS Astrium has started evaluation activities of commercially available 1200 V SiC diodes and also 4.5 kV diodes developed in the frame of the ESA CHPCA (components for high power conditioning application) project. One application is power supply of ion thrusters on satellites which require electric power in the range of 2 to 8 kW at voltages of 1 to 2 kV. Mechanical aerospace applications of polycrystalline SiC

Abstract: Schottky barrier diodes and junction barrier Schottky diodes are investigated by thermal admittance spectroscopy, and by Capacitance-Voltage measurements. Samples are protected with surrounding junction termination extension and p+ ring. Temperature dependence of the doping level is first calculated. Then admittance spectra allow detecting defects and extracting their activation energies and capture cross sections. Results seem to indicate the presence of interfacial defects and defects due to the implantation process.

Abstract: The impact of barrier tunneling on SiC-JBS performance is studied both experimentally and theoretically. We show that although the pinch-off effects associated with the JBS structure can significantly suppress the surface electric field, barrier tunneling still dominates the reverse behavior. Barrier tunneling determines the apparent breakdown voltage, as well as the apparent breakdown voltage vs. forward voltage drop trade-off of the JBS diode in practical applications.

Abstract: The effects of post annealing etch process on electrical performances of a 4H-SiC Schottky diodes without any edge termination were investigated. The post etch was carried out using various dry the dry etch techniques such as Inductively Coupled Plasma (ICP) and Neutral Beam Etch (NBE) in order to eliminate suspicious surface damages occurring during a high temperature ion activation process. The leakage current of diodes treated by NBE measured at -100V was about one order lower than that of diode without post etch and a half times lower than that of diode treated by ICP without a significant degradation of forward electrical characteristics. Based on the above results, the post annealing process was adapted to a junction barrier Schottky diode with a field limiting ring. The blocking voltages of diode without post annealing etch and diodes treated by ICP and NBE were -1038V, -1125V, and -1595V, respectively.