http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

A marigold-like SiC@MoS2 nanoflower with a unique Z-scheme structure efficiently achieves the overall conversion of gas phase CO2 with H2O (CO2 (g) + 2H2O (g) = CH4 + 2O2) without any sacrificial reagents under visible light (λ ≥ 420 nm) irradiation. The CH4 and O2 evolution are 323 and 621 μL·g-1·h-1, and stable throughout 5 cycle reactions of total 40 h. This work demonstrates a breakthrough in artificial photosynthesis with the Z-scheme 1D heterojunction constructed by combining 2D semiconductor and 3D semiconductor based on the transfer balance of photogenerated electron and hole.

Visible-Light Driven Overall Conversion of CO2 and H2O to CH4 and O2 on 3D-SiC@2D-MoS2 Heterostructure.

The need for power semiconductor devices with high-voltage, high- frequency, and high-temperature operation capability is growing, especially for advanced power conversion and military applications, and hence the size and weight of the power electronic system are reduced. Development of 15-kV SiC IGBTs and their impact on utility applications is discussed.

Smart grid technologies

Simple analytical approximation has been obtained to describe the temperature and concentration dependencies of the low-field mobility in gallium nitride (GaN) in wide temperature (50⩽ T ⩽1000 K) and concentration (10 14 ⩽ N ⩽10 19 cm −3 ) ranges. The dependence of the temperature T m at which the mobility μ is at a maximum on the doping level is also obtained. Results obtained can be directly used for computer simulation of GaN-based devices.

Carrier mobility model for GaN

This paper presents a comprehensive short-circuit ruggedness evaluation and numerical investigation of up-to-date commercial silicon carbide (SiC) MOSFETs. The short-circuit capability of three types of commercial 1200-V SiC MOSFETs is tested under various conditions, with case temperatures from 25 to 200 °C and dc bus voltages from 400 to 750 V. It is found that the commercial SiC MOSFETs can withstand short-circuit current for only several microseconds with a dc bus voltage of 750 V and case temperature of 200 °C. The experimental short-circuit behaviors are compared, and analyzed through numerical thermal dynamic simulation. Specifically, an electrothermal model is built to estimate the device internal temperature distribution, considering the temperature-dependent thermal properties of SiC material. Based on the temperature information, a leakage current model is derived to calculate the main leakage current components (i.e., thermal, diffusion, and avalanche generation currents). Numerical results show that the short-circuit failure mechanisms of SiC MOSFETs can be thermal generation current induced thermal runaway or high-temperature-related gate oxide damage.

Temperature-Dependent Short-Circuit Capability of Silicon Carbide Power MOSFETs

For Silicon Carbide (SiC) high-voltage rectifier diodes, contradictions appear when the most important parameter of the diodes, the minority carrier lifetime, is measured by different techniques. A qualitative analysis and a computer simulation have been carried out to clarify the origin of these contradictions. For 4H-SiC p/sup +/n diodes with 6 kV blocking capability, data on residual voltage drop at high current densities, switch-on time, reverse current recovery, and post-injection voltage decay are analyzed. It is shown that the whole set of experimental data can be explained by the existence of a thin (l/spl sim/0.1 /spl mu/m) layer near the metallurgical boundary of the p/sup +/n junction with very small carrier lifetime /spl tau//sub l/ that is essentially smaller than the carrier lifetime /spl tau/ across the remaining part of the 50-/spl mu/m n-base. It is emphasized that the existence of such a layer allows, under certain conditions, the combination of a relatively low residual forward voltage drop and very fast reverse recovery. Approaches to minority carrier lifetime measurements are discussed.

"Paradoxes" of carrier lifetime measurements in high-voltage SiC diodes

Simple analytical approximations are proposed for describing the temperature and concentration dependences of low-field mobility in the main polytypes of silicon carbide (SiC): 6H, 4H and 3C in wide ranges of temperature and concentration. The obtained results can be directly used for the computer simulation of SiC-based devices. Different approaches to the analytical approximation of SiC parameters are critically correlated and analysed.

http://iopscience.iop.org/article/10.1088/0268-1242/17/9/313/pdf

Carrier mobility model for simulation of SiC-based electronic devices

Experimental data on electron and hole mobility in three silicon carbide polytypes, 4H-SiC, 6H-SiC, and 3C-SiC, are analyzed. A semiempirical model is proposed for describing the dependence of the majority carrier mobility on temperature and doping level. The model describes well the accumulated body of experimental data and can be applied to model characteristics of multilayer silicon carbide structures.

Semiempirical Model of Carrier Mobility in Silicon Carbide for Analyzing Its Dependence on Temperature and Doping Level

Steady-state and transient characteristics of 10 kV 4H-SiC diodes have been measured in the temperature interval from 293 to 514 K. The results obtained demonstrate a high level of base modulation: at forward current density jF=180 A cm−2, the differential resistance rd of the diode is 24 times lower than the ohmic resistance r0 of the unmodulated base at room temperature. The minority carrier lifetime τp has been measured by open circuit voltage decay (OCVD) and current recovery time (CRT) techniques. The lifetimes τp values measured by OCVD are 1.55 μs at room temperature and 6.52 μs at T=514 K, which are the highest reported values for SiC diodes. CRT measurements indicate a uniform distribution of carrier lifetime across the diode base. However, comparison of the experimental results with the results of adequate simulation reveals reduced values of electron lifetime in highly doped part of the p+-emitter.

S. N. Yurkov

Papers

Carrier mobility model for GaN

"Paradoxes" of carrier lifetime measurements in high-voltage SiC diodes

Carrier mobility model for simulation of SiC-based electronic devices

Semiempirical Model of Carrier Mobility in Silicon Carbide for Analyzing Its Dependence on Temperature and Doping Level

Steady-state and transient characteristics of 10 kV 4H-SiC diodes