Papers by Keyword: Junction Barrier Schottky (JBS) Diode

Abstract: The effect of the doping concentration and space of both p-grid and FLR on the electrical performances of 4H-SiC JBS diode has been investigated. A 4H-SiC JBS diode with the p-grid space of 3um, the FLR space of 3um, and the doping concentration of 5E18cm-3 showed the highest blocking voltage of 1500V.

Abstract: The development of 10 kV silicon carbide (SiC) MOSFETs and Junction Barrier Schottky (JBS) diodes for application to a 13.8kV 2.7 MVA Solid State Power Substation (SSPS) is shown. The design of half-bridge power modules has extensively used simulation, from electron level device simulations to the system level trade studies, to develop the most efficient module for use in the SSPS. In the work presented within, numerical simulations and experimental results are shown to demonstrate the design and operation of 10 kV JBS diodes. It is shown that JBS diodes at 10 kV can reduce 31% of the switching losses at 20 kHz than the fastest SiC PiN diodes.

Abstract: 4H-SiC Junction Barrier Diodes (JBS) diodes were designed, fabricated and tested. The JBS diodes based on a 45μm thick, 1.4×1015cm-3 doped drift layer with multiple non-uniform spacing guard ring edge termination showed a blocking voltage of over 5kV. The 5kV JBS diode has a forward current density of 108A/cm2 at 3.5V and a specific on resistance (RSP_ON) of 25.2mW·cm2, which is very close to the theoretical RSP_ON of 23.3mΩ·cm2. DC I-V measurement of packaged JBS diodes showed a forward current of 100A at a voltage drop of 4.3V. A half-bridge inverter with a bus voltage up to 2.5kV was used to characterize the high power switching performance of SiC JBS diodes. A large inductance load of 1mH was used to simulate the load of a high power AC induction motor. Compared to a Si PIN diode module, the SiC JBS package reduces diode turn-off energy loss by 30% and Si IGBT turn-on energy loss by 21% at room temperature.

Abstract: Forward and reverse bias performance of 10kV, 10A and 20A junction barrier-controlled Schottky 4H silicon carbide rectifiers are presented. Over a temperature range of 30 to 200°C, the forward current-voltage curves show a normal Schottky rectifier relationship and the reverse current-voltage curves show typical PiN blocking. When operated in reverse-blocking at 125°C and 8kV, the 10A JBS rectifiers are notably stable at less than 5μA of leakage current, despite the large active area of the devices.

Abstract: 4H-SiC SBDs have been developed by many researchers and commercialized for power application devices in recent years. At present time, the issues of an SiC-SBD are lower on-state current and a relatively larger-leakage current at the reverse bias than Si-PN diodes. A JBS (Junction Barrier Schottky) diode was proposed as a structure to realize a lower leakage current. We simulated the electrical characteristics of JBS diodes, where the Schottky electrode was made of molybdenum in order to optimize its performance. We fabricated JBS diodes based on the simulation with a diameter of 3.9mm (11.9 mm2). The JBS diode has a lower threshold voltage of 0.45 V, a large forward current of 40 A at Vf = 2.5V and a high breakdown voltage of 1660 V. Furthermore, the leakage current at 1200 V was remarkably low (Ir = 20 nA).

Abstract: 1.2 kV and 3.5 kV JBS diodes have been fabricated using the same technology process. After 50 hours of DC stress, 1.2 kV diodes do not exhibit any degradation in forward mode whereas the 3.5 kV JBS diodes show a degradation after ten hours. This behaviour has been confirmed by the formation of Stacking Faults clearly illustrated by electroluminescence microscopy in 3.5 kV JBS diodes, whereas it is not the case for the 1.2 kV JBS diodes.

Abstract: DC characteristics and reverse recovery performance of 4H-SiC Junction Barrier Schottky (JBS) diodes capable of blocking in excess of 10 kV with forward conduction of 20 A at a forward voltage of less than 4 V are described. Performance comparisons are made to a similarly rated 10 kV 4H-SiC PiN diode. The JBS diodes show a significant improvement in reverse recovery stored charge as compared to PiN diodes, showing half of the stored charge at 25°C and a quarter of the stored charge at 125°C when switched to 3 kV blocking. These large area JBS diodes were also employed to demonstrate the tremendous advances that have recently been made in 4H-SiC substrate quality.

Abstract: In this paper, we propose new designs of Schottky, JBS and PiN diodes, which process technology is compatible with that of vertical power SiC JFETs. Three novel diode designs are proposed and we report their electrical characteristics. The P+ buried layer implant of the JFET is used for the PiN anode formation and for the P+ islands of the JBS. The Schottky diode differs from a standard Schottky diode since buried rings below the Schottky contact region have been included and the anode metal layer also contacts the buried P+ region at the diode periphery. With this last approach, the resulting Schottky diodes show low leakage currents and surge current capability, with a lower on-state voltage than the JBS.

Abstract: We have investigated the field limiting ring (FLR) geometry dependence of breakdown voltage characteristics for a junction barrier Schottky (JBS)-assisted FLR SiC-SBD. The SiC-SBDs having a guard ring-assisted FLR surrounding a Schottky contact edge and an internal ring inside Schottky contact were fabricated. The breakdown voltage characteristics of the JBS-assisted FLR SiC-SBD are significantly dependent on the width, spacing, and number of FLR. The breakdown voltage characteristic is improved as either the FLR width and FLR number increase or the FLR spacing decreases. Approximately 1650 V maximal breakdown voltage, corresponding to 82% ideal breakdown voltage, is observed with seven FLRs having 5 2m width and 1 2m spacing.

Abstract: 4H-SiC SBDs have been commercialized for power application devices. However, the maximum current of these SBDs is 20A. In this work, we designed a JBS (junction barrier Schottky) diode structure and the fabrication processes to be optimized. The current and breakdown voltage were over 100 A and 660 V at Ir = 1 mA/cm2, respectively. The recovery characteristics of the JBS diode are much superior to those of the Si-FRD while it is comparable to those of the commercially available SiC-SBD at elevated temperatures up to 125°C..