A5036130568- Silicon Carbide Semiconductor Technologies
- Semiconductor materials and devices
- Copper Interconnects and Reliability
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor materials and interfaces
- Thin-Film Transistor Technologies
- ZnO doping and properties
- Ga2O3 and related materials
- Advanced ceramic materials synthesis
- Multilevel Inverters and Converters
- Diamond and Carbon-based Materials Research
- Silicon and Solar Cell Technologies
- Electromagnetic Compatibility and Noise Suppression
- GaN-based semiconductor devices and materials
- Integrated Circuits and Semiconductor Failure Analysis
- HVDC Systems and Fault Protection
- Ion-surface interactions and analysis
- Electronic and Structural Properties of Oxides
- Advanced Photocatalysis Techniques
- 2D Materials and Applications
- Radiation Effects in Electronics
- Surface and Thin Film Phenomena
- Gas Sensing Nanomaterials and Sensors
- MXene and MAX Phase Materials
- High-pressure geophysics and materials
Auburn University
2014-2023
Purdue University West Lafayette
2018
Simon Fraser University
2011-2016
Wolfspeed, Inc. (United States)
2009-2013
Cree (China)
1997-2012
Vanderbilt University
2003-2010
Center for Nanoscale Science and Technology
2007-2009
Korea Research Institute of Chemical Technology
2009
Research Triangle Park Foundation
2009
DEVCOM Army Research Laboratory
2008
A sustainable energy future requires power electronics that can enable significantly higher efficiencies in the generation, distribution, and usage of electrical energy. Silicon carbide (4H-SiC) is one most technologically advanced wide bandgap semiconductor outperform conventional silicon terms handling, maximum operating temperature, conversion efficiency modules. While SiC Schottky diode a mature technology, Metal Oxide Semiconductor Field Effect Transistors are relatively novel there...
Solar-blind photodetection and photoconductive gain >50 corresponding to a responsivity >8 A/W were observed for β-Ga2O3 Schottky photodiodes. The origin of was investigated. Current-voltage characteristics the diodes did not indicate avalanche breakdown, which excludes carrier multiplication by impact ionization as source gain. However, photocapacitance measurements indicated mechanism hole localization above-band gap illumination, suggesting self-trapped formation. Comparison...
A modified Deal Grove model for the oxidation of 4H-SiC is presented, which includes removal carbon species. The applied to data on rates (0001) Si, (0001̄) C, and (112̄0) a faces, are performed in 1 atm dry oxygen temperature range 950–1150 °C. Analysis within provides physical explanation large crystal-face dependent observed.
Unlike the Si-SiO2 interface, SiC-SiO2 interface has large defect densities. Though nitridation been shown to reduce density, effect of H remains an open issue. Here we combine experimental data and results first-principles calculations demonstrate that a Si-C-O bonded interlayer with correlated threefold-coordinated C atoms accounts for observed states, passivation by N atomic H, nature residual defects.
Nitridation of the SiO2/SiC interface yields a reduction in state density, immunity to electron injection, as well increased hole trapping. It is shown that accumulation nitrogen at oxide/semiconductor solely responsible for these three effects. The evolution density states, traps, and traps measured metal-oxide-semiconductor capacitors function content which varied by adjusting gate oxide NO annealing time. A rate equation derived model change observed various energy levels, terms binding...
Hydrogen termination of oxidized silicon in hydrofluoric acid results from an etching process that is now well understood and accepted. This surface has become a standard for studies science important component device processing microelectronics, energy, sensor applications. The present work shows HF carbide (SiC) leads to very different termination, whether the carbon or terminated. Specifically, surfaces are hydrophilic with hydroxyl resulting inability remove last oxygen layer at...
Free electron concentration and carrier mobility measurements on 4H–SiC metal-oxide-semiconductor inversion layers are reported in this article. The key finding is that state-of-the-art nitrided gate oxides, loss of carriers by trapping no longer plays a significant role the current degradation under heavy conditions. Rather, it low (maximum∼60 cm2 V−1 s−1) limits channel current. measured free modeled using charge-sheet model existing models. Possible mechanisms have been discussed based...
Low interface trap density and high channel mobility on nonpolar faces of 4H-SiC, such as the (11[2̅]0) a-face, are fundamental importance in understanding SiC MOS devices. It is also critical for high-voltage trench power MOSFET development. We report new results passivation SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /a-face 4H-SiC using phosphorus, yielding field effect ~125 cm /V · s. revisit conventional NO passivation,...
Phosphorous from P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> is more effective than nitrogen for passivating the 4H-SiC/SiO interface. The peak value of field-effect mobility 4H-SiC metal-oxide-semiconductor transistors (MOSFETs) after phosphorus passivation approximately 80 cm <sup xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V·s. However, converts SiO layer to...
Alkali (Rb and Cs) alkaline earth (Ca, Sr, Ba) elements have been investigated as interface passivation materials for metal-oxide-semiconductor field-effect transistors (MOSFETs) on 4H-SiC (0001). While the alkali Rb Cs result in mobility (μFE) values &gt; 25 cm2/V·s, Sr Ba resulted higher μFE of 40 85 respectively. The Ba-modified MOSFETs show a slight decrease with heating to 150 °C, expected when is not interface-trap-limited, but phonon-scattering-limited. With layer, state density...
In this paper, the temperature dependence of turn-on characteristics Schottky barrier diodes fabricated on oriented n-type β-Ga2O3 is reported. The height (qΦbn) and ideality factor (n) for Ni- was found to be 1.08 ± 0.05 eV 1.19 respectively at room temperature. effective Richardson constant (A **) determined 42.96 A cm−2 K−2, in close agreement with theoretical value. At low temperatures (85–273 K), current–voltage reveal a strong heights factors corresponding deviation from extracted...
Channel mobility of >100 cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{2}$ </tex-math></inline-formula> V notation="LaTeX">$^{-1}$ s has been obtained on enhancement mode 4H-SiC MOSFETs using an antimony (Sb) doped surface channel in conjunction with nitric oxide (NO) postoxidation annealing. Temperature dependence the indicates that Sb, being n-type dopant, reduces electric field while NO anneal...
The electrical properties of interfaces and the impact post-deposition annealing have been investigated in gate oxides formed by low pressure chemical vapor deposition (LPCVD SiO2) atomic layer (Al2O3) on (2¯01) oriented n-type β-Ga2O3 single crystals. Capacitance-voltage based methods used to extract interface state densities, including densities slow ‘border’ traps at dielectric-Ga2O3 interfaces. It was observed that SiO2-β-Ga2O3 has a higher border trap density than Al2O3-β-Ga2O3. An...
Nitric oxide postoxidation anneal results in a significant decrease of defect state density (Dit) near the conduction bandedge n-4H–SiC at oxide/(112̄0) 4H–SiC interface. Comparison with measurements on conventional (0001) Si-terminated face shows similar interface following passivation. Medium energy ion scattering provides quantitative measure nitrogen incorporation SiO2/SiC
Interface trap passivation at the SiO2∕carbon-terminated (0001¯) face of 4H-SiC utilizing nitridation and hydrogenation has been evaluated. The SiO2∕SiC interface, created by dry thermal oxidation on C face, shows appreciably higher interface state density near conduction band compared to (0001) Si face. A postoxidation anneal in nitric oxide followed a postmetallization hydrogen results dramatic reduction over an order magnitude band. electrical measurements have correlated with interfacial...
Nitrogen incorporation at the SiO2/SiC interface via high temperature nitric oxide annealing leads to passivation of electrically active defects, yielding improved inversion mobility in semiconductor. However, we find that such nitrided oxides can possess a larger density hole traps than as-grown oxides, which is detrimental reliability devices (e.g., lead large threshold voltage instabilities and accelerated failure). Three different charge injection techniques are used characterize this...
Postoxidation annealing in nitric oxide (NO) results a significant reduction of electronic states at SiO2/4H-SiC interfaces. Measurements electron trapping dynamics interface both thermally oxidized and NO annealed interfaces were performed using constant-capacitance deep level transient spectroscopy (CCDLTS) double-CCDLTS. We show that the state density as-oxidized samples consists overlapping distributions traps have distinctly different capture cross sections. The dominant trap...
We present our latest developments in ultra high voltage 4H-SiC IGBTs. A 6.7 mm x N-IGBT with an active area of 0.16 cm2 showed a blocking 12.5 kV, and demonstrated room temperature differential specific on-resistance 5.3 mΩ-cm2 gate bias 20 V. P-IGBT exhibited record 15 while showing 24 mΩ-cm2. comparison between P- N- IGBTs is provided this paper.
The higher critical electric field of β-gallium oxide (Ga2O3) gives promise to the development next generation power electronic devices with improved size, weight, power, and efficiency over current state-of-the-art wide bandgap based on 4H-silicon carbide (SiC) gallium nitride (GaN). However, it is expected that Ga2O3 will encounter serious thermal issues due poor conductivity material. In this work, self-heating in Schottky barrier diodes under different regimes diode operation was...
Silicon has been the semiconductor of choice for microelectronics largely because unique properties its native oxide (SiO2) and Si/SiO2 interface. For high-temperature and/or high-power applications, however, one needs a with wider energy gap higher thermal conductivity. carbide right same as Si. However, in late 1990’s it was found that SiC/SiO2 interface had high trap densities, resulting poor electron mobilities. Annealing hydrogen, which is key to quality interfaces, proved ineffective....
Dry oxidations between 0.25 and 4 atm at 1150 °C are used to characterize the pressure dependence of growth kinetics SiO2 along three orientations 4H-SiC polytype. The curves studied using Deal-Grove model. extracted linear parabolic constants found scale linearly with up 2 atm. However, data indicate that (0001) Si-face exhibits a retarded rate above It is also that, like Si, there critical oxide thickness below which linear-parabolic model cannot be applied. This value 36 40 nm for on...
In this paper, we review the performance, reliability, and robustness of current 4H-SiC power DMOSFETs. Due to advances in device materials technology, high power, large area DMOSFETs (1200 V, 67 A 3000 30 A) can be fabricated with reasonable yields. The availability devices has enabled demonstration first MW class, all SiC modules. Evaluations 1200 V showed that offer avalanche exceeding those commercially available silicon MOSFETs, have sufficient short circuit required most motor drive...
The irradiation and annealing responses of 4H-SiC MOS devices with nitrided oxides are investigated at varying biases. Radiation-induced hole trapping dominates the radiation response these devices. Switching bias between can lead to significant enhancement degradation in some cases. Positive followed by negative is found be worst-case for combined degradation. After irradiation, reversibility charge observed switched-bias n-substrate capacitors, while enhanced p-substrate capacitors. These...