4H-SiC JBS Diodes Research Articles

Impact of Electron Irradiation on the ON-State Characteristics of a 4H–SiC JBS Diode

The ON-state characteristics of a 1.7-kV 4H–SiC junction barrier Schottky diode were studied after 4.5-MeV electron irradiation. Irradiation doses were chosen to cause a light, strong, and full doping compensation of an epitaxial layer. The diodes were characterized using Deep Level Transient Spectroscopy, $C$ – $V$ (T), and $I$ – $V$ measurements without postirradiation annealing. The calibration of model parameters of a device simulator, which reflects the unique defect structure caused by the electron irradiation, was verified up to 2000 kGy. The quantitative agreement between simulation and measurement requires: 1) the Shockley–Read–Hall model with at least two deep levels on the contrary to ion irradiation and 2) a new model for enhanced mobility degradation due to radiation defects. The diode performance at high electron fluences is shown to be limited by the doping compensation at the epitaxial layer.

Impact of Design on Electrical Characteristics of 3.5 kV 4H-SiC JBS Diode

This work reports on the fabrication and electrical characterization of 3 different diodes. The first one is a Schottky diode with a single 50 mm P+ ring between the edge termination and the active area. The two other diodes are JBS with a 3 mm P+ strips separated by 4 mm and 8 mm respectively. The breakdown voltage ranges from 2.7kV up to 3.7kV depending on the P+/N area. The 3 different diodes exhibit a similar on-resistance versus the temperature behavior. Moreover, no contribution of the bipolar conduction is observed and no degradation has been observed when a forward stress is performed in forward mode and also in reverse.

Development of 10 kV 4H-SiC JBS diode with FGR termination

The design, fabrication, and electrical characteristics of the 4H-SiC JBS diode with a breakdown voltage higher than 10 kV are presented. 60 floating guard rings have been used in the fabrication. Numerical simulations have been performed to select the doping level and thickness of the drift layer and the effectiveness of the edge termination technique. The n-type epilayer is 100 μm in thickness with a doping of 6 × 1014 cm−3. The on-state voltage was 2.7 V at JF = 13 A/cm2.

Simulation, Fabrication and Characterization of 4500V 4H-SiC JBS Diode

4H-SiC JBS diode with breakdown voltage higher than 4.5 kV, has been successfully fabricated on 4H-SiC wafers with epitaxial layer. In this paper we report the design, the fabrication, and the electrical characteristics of 4H-SiC JBS diode. Numerical simulations have been performed to select the doping level and thickness of the drift layer and the effectiveness of the edge termination technique. The epilayer properties of the N-type are 55 μm with a doping of 9×1014 cm−3. The diodes were fabricated with a floating guard rings edge termination. The on-state voltage was 4V at JF =80 A/cm2

Simulation, Fabrication and Characterization of 6500V 4H-SiC JBS Diode

4H-SiC JBS diode with breakdown voltage higher than 6.5 kV has been successfully fabricated on 4H-SiC wafers with epitaxial layer. In this paper, the simulation, the fabrication, and the electrical characteristics of 4H-SiC JBS diode were reported. The drift layer thickness and doping are 55 μm and 9×1014cm3respectively. 60 floating guard rings edge were fabricated as termination. The on-state voltage was 4 V at JF= 7A.

Leakage currents in 4H-SiC JBS diodes

Leakage currents in high-voltage 4H-SiC diodes, which have an integrated (p-n) Schottky structure (Junction Barrier Schottky, JBS), have been studied using commercial diodes and specially fabricated (based on a commercial epitaxial material) test Schottky diodes with and without the JBS structure. It is shown that (i) the main role in reverse charge transport is played by SiC crystal structure defects, most probably, by threading dislocations (density ∼104 cm−2), and (ii) the JBS structure, formed by the implantation of boron, partially suppresses the leakage currents (by up to a factor of 10 at optimal separation, 8 μm between local p-type regions).

DLTS Measurements on 4H-SiC JBS-Diodes with Boron Implanted Local P-N Junctions

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.

Analysis of Surface Defects on the Reverse Characteristics of 4H-SiC JBS Diode

The good relations between the reverse characteristics of 4H-SiC JBS diodes and the surface defects were obtained. The reverse characteristics of 4H-SiC JBS diodes were categorized in three groups as follows: (A) low blocking voltage, (B) high leakage current and (C) low leakage current. The groups of (A) and (B) were caused by the existences of the micropipe and small particles, and the carrot-like defects on the SiC surfaces, respectively. In group (C), there was no defect on the surfaces observed by the optical microscope. The structure of carrot-like defect was analyzed by the cathode-luminescence and TEM.

Effect of the Doping Concentration and Space of Both p-Grid and Field Limiting Ring on 4H-SiC Junction Barrier Schottky Diode with Single Ion Implantation Process

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.

Reliability Aspects of High Voltage 4H-SiC JBS Diodes

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.

Comparison of Si and SiC diodes during operationin three-phase inverter driving ac induction motor

4H-SiC JBS diodes have been used in an inverter circuit, driving an actual three-phase ac induction motor at power levels up to 2.2 HP. Switching waveforms were measured and compared between inverters based on Si PiN diodes and 4H-SiC MPS diodes. The results clearly show a significant reduction in power dissipation, in both the diode and the IGBT switch, when SiC diodes replace the Si diodes. The reduction is most evident at the higher temperatures.

3.6 kV 4H-SiC JBS Diodes with Low RonS

3.6 kV 4H-SiC JBS Diodes with Low RonS