A5023839579- Silicon Carbide Semiconductor Technologies
- Semiconductor materials and devices
- Advanced ceramic materials synthesis
- Thin-Film Transistor Technologies
- Copper Interconnects and Reliability
- Silicon and Solar Cell Technologies
- Advanced Surface Polishing Techniques
- Semiconductor materials and interfaces
- Aluminum Alloys Composites Properties
- GaN-based semiconductor devices and materials
- Induction Heating and Inverter Technology
- Diamond and Carbon-based Materials Research
- Electromagnetic Compatibility and Noise Suppression
- Advanced Machining and Optimization Techniques
- Plasma Diagnostics and Applications
- Metal and Thin Film Mechanics
- Advanced machining processes and optimization
- Ergonomics and Musculoskeletal Disorders
- Integrated Circuits and Semiconductor Failure Analysis
- ZnO doping and properties
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor Quantum Structures and Devices
- Effects of Vibration on Health
National Institute of Advanced Industrial Science and Technology
2015-2024
Toto (Japan)
2010-2024
Advanced Power Electronics (United States)
2014-2024
Tohoku University
2015-2020
Nagoya University
2020
Toyota Motor Corporation (Japan)
2020
Central Research Institute of Electric Power Industry
2016-2018
Kyoto University
2016-2018
Fuji Electric (Japan)
2016-2018
Kyoto Katsura Hospital
2017-2018
We investigated the dependency of minority carrier lifetimes on nitrogen concentration, temperature, and injected concentration for highly nitrogen-doped 4H-SiC epilayers. The greatly shortened when exceeded 1018 cm−3 through enhancing direct band-to-band Auger recombination showed a slight variation in temperature range from room (RT) to 250 °C. epilayer with 9.3 × exhibited very short lifetime 38 ns at RT 43 were confirmed maintain values even after subsequent annealing 1700 PiN diodes...
The growth of Shockley type stacking faults in p-i-n diodes fabricated on the C-face 4H-SiC during forward current operation was investigated using Berg-Barrett X-ray topography and photoluminescence imaging. After experiment, were generated from very short portions basal plane dislocations lower than conversion points to threading edge epitaxial layer. behavior discussed. Growth substrates not observed.
Ultrahigh-voltage silicon carbide (SiC) devices [p-i-n diodes and insulated-gate bipolar transistors (IGBTs)] switching test have been investigated. As a result, we succeeded in developing 13-kV p-i-n diode, 15-kV p-channel IGBT, 16-kV flip-type n-channel implantation epitaxial IGBT with low differential specific on-resistance ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <inline-formula xmlns:xlink="http://www.w3.org/1999/xlink">...
This paper describes the fabrication of a SiC-based high electron mobility transistor (HEMT). A single-crystal 3C–SiC layer was grown on C-face 4H–SiC substrate, and 2D gas induced at 3C–SiC/4H–SiC heterointerface due to unique polarization physics. The measured Hall 2DEG 586 cm2/V s room temperature. Source, gate, drain electrodes were fabricated surface. current for SiC-HEMT be 47.5 mA/mm, transconductance estimated 13.5 mS/mm.
Impacts of extended defects on performance and reliability SiC power devices are reviewed. Threading dislocations in the state-of-the-art wafers do not work as major leakage paths macroscopic generated during epitaxial process more harmful. A basal plane dislocation is a killing defect bipolar because Shockley-type stacking fault (SSF) expanded from when electron-hole recombination energy given. After classification SSF-expansion patterns, types SSFs (triangular-shaped bar-shaped SSFs) their...
We investigated the relationship between dislocation velocity and injected carrier concentration on expansion of single Shockley-type stacking faults by monitoring electroluminescence from 4H-SiC PiN diodes with various anode Al concentrations. The was calculated using a device simulation that took into account measured accumulated charge in drift layer during diode turn-off. strongly dependent hole concentration, which represents excess concentration. activation energy quite small (below...
The correlation between thermal oxide reliability and dislocations in n-type 4H-SiC (0001) epitaxial wafers has been investigated. oxides were grown by dry oxidation at 1200°C followed nitrogen postoxidation annealing. Charge-to-breakdown values of decrease with an increase the number a gate-oxide-forming area. Two types dielectric breakdown modes, edge dislocation-related breakdown, confirmed Nomarski microscopy. In addition, it is revealed that basal plane dislocation most common cause mode.
Recent development of device fabrication SiC is awaiting detailed study the machining surfaces. We scratched 4H-SiC surfaces with a sliding microindenter made chip, and characterized affected layers by micro-Raman spectroscopy. The results Raman measurement scratching grooves revealed that there were residual stress, defects, stacking faults. Furthermore, heavy load, we found clusters amorphous SiC, Si, carbon, graphite in grooves. Analysis spectra showed amorphization occurs first surface...
The improvements of the AlGaAs solar cell grown on Si substrate and AlGaAs/Si tandem by metalorganic chemical vapor deposition have been investigated. active-area conversion efficiency Al0.1Ga0.9As as high 12.9% has obtained improving growth sequence adopting an Al compositionally graded band emitter layer. A monolithic with 19.9% 20.6% (AM0 1 sun at 27 °C) under two-terminal four-terminal configurations, respectively, is demonstrated.
The surface morphology and lattice defect structures in the subsurface regions of 4H-SiC wafers introduced during chemo-mechanical polishing (CMP) were studied by scanning electron microscopy transmission microscopy. It is known that local damage consisting high-density defects current CMP, however, optical showed was very flat clean without any presence defects. Specifically, this study focused on detailed analysis such structures. locally consisted nano-scale scratches, basal-plane...
The origin of expanded single Shockley-type stacking faults in forward-current degradation 4H-SiC p–i–n diodes was investigated by the stress-current test. At a density lower than 25 A cm−2, triangular were formed from basal-plane dislocations epitaxial layer. higher 350 both and long-zone-shaped that converted into threading edge near interface between layer substrate. In addition, conversion depth fault inside substrate deeper interface. These results indicate strongly affects threshold at...
To investigate the mechanism of contraction/expansion behavior Shockley stacking faults (SSFs) in 4H-SiC p–i–n diodes, dependences SSF on temperature and injection current density were investigated by electroluminescence image observation. We both triangle- bar-shaped SSFs at four levels. All this study show similar dependences. found that expansion a high was converted to contraction certain value as decreased is temperature-dependent. It has been confirmed behavior, which considered...
The formation of parasitic SiC inclusions was completely suppressed during solution growth using an liner crucible that provided conditions saturated only with SiC. In contrast, formed in a graphite as carbon source. For crucible, the frequency increased Cr content solvent, which ascribed to increasing C solubility. dissolution behavior crucibles containing Si–Cr solvents investigated; we found thickness Si–SiC–C composite layer on wall decreased solvent and disappeared for higher than 40...
Abstract The temperature-dependent Hall mobilities (µ_{Hall}(T)) of heavily Al-doped 4H-SiC, fabricated using chemical vapor deposition with Al concentrations (C_{Al}) exceeding 10^{19} cm^{-3}, are analyzed to develop p^{+}-type substrates suitable as collectors for n-channel insulated-gate bipolar transistors. In the band conduction region, µ_{Hall}(T) in valence is governed by acoustic phonon scattering at high temperatures and ionized impurity low temperatures. allowed miniband formed...
For n-type 4H-SiC crystals with carrier concentrations between 2 × 1017 and 2.5 1020 cm−3, Fano interference of the folded transverse acoustic (FTA) doublet modes was observed. The line-shape parameters were shown to vary concentration. It is proposed that peak shifts in FTA resulting from an electronic continuum state can be used measure concentration for up cm−3. In addition, relative intensity varies markedly above 5 1018 This suggests mode coupling occurs components. variation ratio...
Flip-type n-channel implantation and epitaxial (IE)-IGBT on 4H-SiC carbon face with an p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">++</sup> collector layer was investigated. In this study, we employed the IEMOSFET as a MOSFET structure original wet gate oxidation method, to realize high channel mobility. We were able achieve ultrahigh blocking voltage of more than 16 kV, extremely low forward drop 5 V at 100 A/cm...
Ultrahigh-voltage SiC flip-type n-channel implantation and epitaxial (IE)-IGBTs were developed, the static dynamic performance was investigated. A large device (8 mm × 8mm) with a blocking voltage greater than 16 kV achieved, an on-state current of 20 obtained at low (V on ) 4.8 V. R diff 23 mΩ·cm 2 V = In order to evaluate switching characteristics IE-IGBT, ultrahigh-voltage power modules assembled. chopper circuit configuration used IE-IGBT. Smooth turn-off waveforms successfully CE 6.5 I...
Nanoscale understanding of high-temperature crystal growth dynamics in solution has been a challenge to be tackled by many researchers engaged investigating processes for bulk single growth. Here we propose new approach situ observation at buried solid/liquid interface using conventional confocal laser scanning microscope. In the 4H-SiC with Si–Ni based alloy flux as model system, show ability quantitatively analyze step motions growing SiC on nanoscale high temperatures up 1700 °C vacuum....
We report SiC wafer polishing study to achieve high throughput with extremely flat, smooth and damageless surface. The consists of three process, grinding, lapping chemical mechanical (CMP), which are completed in shortest about 200 minutes total for 2 inch wafer. Specimens 4H- 6H-SiC were provided from slicing single crystal as wafers oriented (0001) 0 or 8 degrees offset angle toward <112 _ 0>. By the first grinding using a diamond whetstone wheel, we realized flat surface on small...