Investigation of 3.3 kV 4H-SiC DC-FSJ MOSFET Structures

This research proposes a novel 4H-SiC power device structure—different concentration floating superjunction MOSFET (DC-FSJ MOSFET). Through simulation via Synopsys Technology Computer Aided Design (TCAD) software, compared with the structural and static characteristics of the traditional vertical MOSFET, DC-FSJ MOSFET has a higher breakdown voltage (BV) and lower forward specific on-resistance (Ron,sp). The DC-FSJ MOSFET is formed by multiple epitaxial technology to create a floating P-type structure in the epitaxial layer. Then, a current spreading layer (CSL) is added to reduce the Ron,sp. The floating P-type structure depth, epitaxial layer concentration and thickness are optimized in this research. This structure can not only achieve a breakdown voltage over 3300 V, but also reduce Ron,sp. Under the same conditions, the Baliga Figure of Merit (BFOM) of DC-FSJ MOSFET increases by 27% compared with the traditional vertical MOSFET. Ron,sp is 25% less than that of the traditional vertical MOSFET.

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A New Split Gate Resurf Stepped Oxide UMOSFET Structure with High Doped Epitaxial Layer for Improving Figure of Merit (FOM)

Applied Sciences ◽

10.3390/app10217895 ◽

2020 ◽

Vol 10 (21) ◽

pp. 7895

Author(s):

Runze Chen ◽

Lixin Wang ◽

Hongkai Zhang ◽

Mengyao Cui ◽

Min Guo

Keyword(s):

Electric Field ◽

Epitaxial Layer ◽

Computer Aided Design ◽

Figure Of Merit ◽

Cost Effective ◽

Oxide Semiconductor ◽

Fabrication Procedure ◽

Conventional Structure ◽

Aided Design ◽

Reduced Surface

The split gate resurf stepped oxide with highly doped epitaxial layer (HDSGRSO) UMOSFET has been proposed. The epitaxial layer of HDSGRSO u-shape metal oxide semiconductor field effect transistor (UMOSFET) has been divided into three parts: the upper epitaxial layer, the lower epitaxial layer and the middle epitaxial layer with higher doping concentration. The research shows that the reduced SURface field (RESURF) active has been enhanced due to the high doped epitaxial layer, which can modulate the electric field distribution and reduce the internal high electric field. Therefore, the HDGRSO UMOSFET has a higher breakdown voltage (BV), a lower on-state specific resistance (RSP) and a better figure of merit (FOM). According to the results of Technology Computer Aided Design (TCAD) simulations, the FOM (BV2/RSP) of HDSGRSO UMOSFET has been improved by 464%, and FOM (RSP × Qgd) of HDSGRSO UMOSFET has been reduced by 27.9% compared to the conventional structure, respectively, when the BV is 240 V. Furthermore, there is no extra special process required in this advanced fabrication procedure, which is relatively cost-effective and achievable.

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Theoretical and Experimental Study of 13.4 kV/55 A SiC PiN Diodes with an Improved Trade-Off between Blocking Voltage and Differential On-Resistance

Materials ◽

10.3390/ma12244186 ◽

2019 ◽

Vol 12 (24) ◽

pp. 4186

Author(s):

Yuewei Liu ◽

Ruixia Yang ◽

Yongwei Wang ◽

Zhiguo Zhang ◽

Xiaochuan Deng

Keyword(s):

Breakdown Voltage ◽

Figure Of Merit ◽

Pin Diode ◽

Potential Candidate ◽

Device Structure ◽

Pin Diodes ◽

Trade Off ◽

Blocking Voltage ◽

Process Complexity ◽

A Current

In this paper, a 13.4 kV/55 A 4H-silicon carbide (SiC) PiN diode with a better trade-off between blocking voltage, differential on-resistance, and technological process complexity has been successfully developed. A multiple zone gradient modulation field limiting ring (MGM-FLR) for extremely high-power handling applications was applied and investigated. The reverse blocking voltage of 13.4 kV, close to 95% of the theoretical value of parallel plane breakdown voltage, was obtained at a leakage current of 10 μA for a 100 μm thick, lightly doped, 5 × 1014 cm−3 n-type SiC epitaxial layer. Meanwhile, a fairly low differential on-resistance of 2.5 mΩ·cm2 at 55 A forward current (4.1 mΩ·cm2 at a current density of 100 A/cm2) was calculated for the fabricated SiC PiN with 0.1 cm2 active area. The highest Baliga’s figure-of-merit (BFOM) of 72 GW/cm2 was obtained for the fabricated SiC PiN diode. Additionally, the dependence of the breakdown voltage on transition region width, number of rings in each zone, as well as the junction-to-ring spacing of SiC PiN diodes is also discussed. Our findings indicate that this proposed device structure is one potential candidate for an ultra-high voltage power system, and it represents an option to maximize power density and reduce system complexity.

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Physics-Based TCAD Simulation and Calibration of 600 V GaN/AlGaN/GaN Device Characteristics and Analysis of Interface Traps

Micromachines ◽

10.3390/mi12070751 ◽

2021 ◽

Vol 12 (7) ◽

pp. 751

Author(s):

Yu-Lin Song ◽

Manoj Kumar Reddy ◽

Luh-Maan Chang ◽

Gene Sheu

Keyword(s):

Conduction Band ◽

Computer Aided Design ◽

Measurement Data ◽

High Electron Mobility Transistor ◽

High Electron ◽

Device Structure ◽

Gan Hemt ◽

Fixed Charges ◽

Vertical Electric Field ◽

Aided Design

This study proposes an analysis of the physics-based TCAD (Technology Computer-Aided Design) simulation procedure for GaN/AlGaN/GaN HEMT (High Electron Mobility Transistor) device structures grown on Si (111) substrate which is calibrated against measurement data. The presence of traps and activation energies in the device structure will impact the performance of a device, the source of traps and position of traps in the device remains as a complex exercise until today. The key parameters for the precise tuning of threshold voltage (Vth) in GaN transistors are the control of the positive fixed charges −5 × 1012 cm−2, donor-like traps −3 × 1013 cm−2 at the nitride/GaN interfaces, the energy of the donor-like traps 1.42 eV below the conduction band and the acceptor traps activation energy in the AlGaN layer and buffer regions with 0.59 eV below the conduction band. Hence in this paper, the sensitivity of the trap mechanisms in GaN/AlGaN/GaN HEMT transistors, understanding the absolute vertical electric field distribution, electron density and the physical characteristics of the device has been investigated and the results are in good agreement with GaN experimental data.

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Ground Plane Impact on Performance of Relaxed Ge FinFETs

Journal of Integrated Circuits and Systems ◽

10.29292/jics.v14i1.55 ◽

2019 ◽

Vol 14 (1) ◽

pp. 1-6

Author(s):

Alberto Vinícius Oliveira ◽

Guilherme Vieira Gonçalves ◽

Paula Ghedini Der Agopian ◽

João Antonio Martino ◽

Jérôme Mitard ◽

...

Keyword(s):

Threshold Voltage ◽

Computer Aided Design ◽

Doping Concentration ◽

Ground Plane ◽

Subthreshold Swing ◽

Voltage Variation ◽

Electrostatic Coupling ◽

P Type ◽

Aided Design ◽

Channel Region

The implementation of a barrier potential layer underneath the channel region, well known as Ground Plane (GP) implantation, and its influence on the performance of relaxed germanium pFinFET devices is investigated in this manuscript. This study aims to explain the fin width dependence of the threshold voltage from experimental data and evaluates the ground plane doping concentration and its depth influence on relaxed p-type channel germanium FinFET parameters, as threshold voltage, transconductance and subthreshold swing, through Technology Computer-Aided Design (TCAD) numerical simulations. The threshold voltage variation reaches up to 80 mV from the narrowest device to the widest one, considering the studied range of ground plane doping concentration. Concerning the subthreshold swing parameter, neither the GP doping concentration, nor its depth play a significant role since the electrostatic coupling is predominant.

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Device Design Assessment of GaN Merged P-i-N Schottky Diodes

Electronics ◽

10.3390/electronics8121550 ◽

2019 ◽

Vol 8 (12) ◽

pp. 1550 ◽

Cited By ~ 1

Author(s):

Yuliang Zhang ◽

Xing Lu ◽

Xinbo Zou

Keyword(s):

Breakdown Voltage ◽

Computer Aided Design ◽

Schottky Diodes ◽

Schottky Contact ◽

Background Concentration ◽

Model Parameters ◽

Design Assessment ◽

Blocking Voltage ◽

Aided Design ◽

Drift Layer

Device characteristics of GaN merged P-i-N Schottky (MPS) diodes were evaluated and studied via two-dimensional technology computer-aided design (TCAD) after calibrating model parameters and critical electrical fields with experimental proven results. The device’s physical dimensions and drift layer concentration were varied to study their influence on the device’s performance. Extending the inter-p-GaN region distance or the Schottky contact portion could enhance the forward conduction capability; however, this leads to compromised electrical field screening effects from neighboring PN junctions, as well as reduced breakdown voltage. By reducing the drift layer background concentration, a higher breakdown voltage was expected for MPSs, as a larger portion of the drift layer itself could be depleted for sustaining vertical reverse voltage. However, lowering the drift layer concentration would also result in a reduction in forward conduction capability. The method and results of this study provide a guideline for designing MPS diodes with target blocking voltage and forward conduction at a low bias.

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Doping Concentration Optimization for Ultra-Low-Loss 4H-SiC Floating Junction Schottky Barrier Diode (Super-SBD)

Materials Science Forum ◽

10.4028/www.scientific.net/msf.615-617.655 ◽

2009 ◽

Vol 615-617 ◽

pp. 655-658 ◽

Cited By ~ 4

Author(s):

Chiharu Ota ◽

Johji Nishio ◽

Kazuto Takao ◽

Tetsuo Hatakeyama ◽

Takashi Shinohe ◽

...

Keyword(s):

Schottky Barrier ◽

Breakdown Voltage ◽

Dynamic Characteristics ◽

Figure Of Merit ◽

Doping Concentration ◽

Drift Region ◽

Static Characteristics ◽

Low Loss ◽

Significant Lowering ◽

Floating Layer

Previous simulation works and experiments on the loss of 4H-SiC floating junction Schottky barrier diodes (Super-SBDs) show that the loss is related to the doping concentration in the drift region and the pattern of the floating layer. The effect of the doping concentration for lowering the loss is characterized the breakdown voltage (Vbd) and the on-state resistances (RonS) of the Super-SBDs based on Baliga’s figure of Merit (BFOM). Experimental devices with two doping concentrations in the drift region are fabricated to investigate the static characteristics: Vbd and RonS. The Vbd of the Super-SBDs is close to the simulation result, near 3000 V. However the tendency of the Vbd by the doping concentration is not similar to the simulation result. And the RonS are about 3.22 mcm2 which is higher than that of simulation result. The doping concentration optimized in this study does not show significant lowering loss and the design of the floating layer in the termination region affect the low-loss static characteristics of the Super-SBD. In addition, adopting PiN structure with floating layer (Super-PiN) affects the low-loss dynamic characteristics, optimizing the doping concentration in the drift region. We conclude that the fabricated Super-SBDs with the floating layer in the termination region, the drift region with a doping concentration of 1.01016 cm-3 and mesa-shaped termination structure, have excellent Vbd of 2990 V which is almost same as that of simulation result and RonS of 3.22 mcm2.

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Investigation of the SiC Transistor and Diode Nuclear Detectors at 8 MeV Proton Irradiation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.483-485.1025 ◽

2005 ◽

Vol 483-485 ◽

pp. 1025-1028 ◽

Cited By ~ 4

Author(s):

Nikita B. Strokan ◽

Alexander M. Ivanov ◽

N.S. Savkina ◽

Alexander A. Lebedev ◽

Vitalii V. Kozlovski ◽

...

Keyword(s):

Schottky Barrier ◽

Epitaxial Layer ◽

Proton Irradiation ◽

Type Structure ◽

Particle Detectors ◽

Nuclear Particle ◽

P Type ◽

Nuclear Detectors ◽

Mev Protons

Nuclear-particle detectors based on SiC with a structure composed of an n+-type substrate, a p-type epitaxial layer, and a Schottky barrier are studied. Structures with a ~10-µm-thick 6H-SiC layer exhibit transistor properties, whereas those with a ~30-µm-thick 4H-SiC layer exhibit diode properties. It is established that a more than tenfold amplification of the signal is observed in the transistor-type structure. The amplification is retained after irradiation with 8-MeV protons with a dose of at least 5 × 10 13 cm –2 ; in this case, the resolution is ≤ 10%. Amplification of the signal was not observed in the structures of diode type. However, there were diode-type detectors with a resolution of ≈ 3%, which is acceptable for a number of applications, even after irradiation with the highest dose of 2 × 10 14 cm.

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Improvement in Turn-Off Loss of the Super Junction IGBT with Separated n-Buffer Layers

Micromachines ◽

10.3390/mi12111422 ◽

2021 ◽

Vol 12 (11) ◽

pp. 1422

Author(s):

Ki-Yeong Kim ◽

Joo-Seok Noh ◽

Tae-Young Yoon ◽

Jang-Hyun Kim

Keyword(s):

Breakdown Voltage ◽

Computer Aided Design ◽

Buffer Layers ◽

Simulation Tool ◽

Electrical Characteristics ◽

Insulated Gate Bipolar Transistor ◽

Computer Aided ◽

Long Time ◽

Tcad Simulation ◽

Aided Design

In this study, we propose a super junction insulated-gate bipolar transistor (SJBT) with separated n-buffer layers to solve a relatively long time for carrier annihilation during turn-off. This proposition improves the turn-off characteristic while maintaining similar on-state characteristics and breakdown voltage. The electrical characteristics of the devices were simulated by using the Synopsys Sentaurus technology computer-aided design (TCAD) simulation tool, and we compared the conventional SJBT with SJBT with separated n-buffer layers. The simulation tool result shows that turn-off loss (Eoff) drops by about 7% when on-state voltage (Von) and breakdown voltage (BV) are similar. Von increases by about 0.5% and BV decreases by only about 0.8%.

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Computer-Aided Design Applied to a Model of a Chassis Type Structure Using Finite Element Techniques

Proceedings of the Institution of Mechanical Engineers Automobile Division ◽

10.1243/pime_auto_1969_184_009_02 ◽

1969 ◽

Vol 184 (1) ◽

pp. 15-24

Author(s):

R. Ali ◽

J. L. Hedges ◽

B. Mills

Keyword(s):

Finite Element ◽

Computer Program ◽

Computer Aided Design ◽

Computation Time ◽

Type Structure ◽

Scale Model ◽

Mode Shapes ◽

Nodal Displacements ◽

Element Technique ◽

Aided Design

The finite element technique has been used for the examination of a chassis-type structure. A computer program was developed to predict the static and dynamic behaviour of frames. The program is quite general but its use has been restricted to structures consisting of beam elements only. A scale model of a production car chassis was made in perspex. Nodal displacements of the model, in bending and torsion, natural frequencies and corresponding mode shapes were predicted by the computer program and confirmed experimentally in the laboratory. Several coarser idealizations of the model were examined to study the effect on the accuracy of predictions and the computation time.

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Comparison between Occlusal Errors of Single Posterior Crowns Adjusted Using Patient Specific Motion or Conventional Methods

Applied Sciences ◽

10.3390/app10249140 ◽

2020 ◽

Vol 10 (24) ◽

pp. 9140

Author(s):

Ye-Chan Lee ◽

Chunui Lee ◽

June-Sung Shim ◽

Ji-Man Park ◽

Yooseok Shin ◽

...

Keyword(s):

Digital Technology ◽

Computer Aided Design ◽

Occlusal Surface ◽

Patient Specific ◽

Average Deviation ◽

Occlusal Surfaces ◽

Conventional Methods ◽

Map Analysis ◽

Aided Design ◽

A Current

Recently, digital technology has been used in dentistry to enhance accuracy and to reduce operative time. Due to advances in digital technology, the integration of individual mandibular motion into the mapping of the occlusal surface is being attempted. The Patient Specific Motion (PSM) is one such method. However, it is not clear whether the occlusal design that is adjusted using PSM could clinically show reduced occlusal error compared to conventional methods based on static occlusion. In this clinical comparative study including fifteen patients with a single posterior zirconia crown treatment, the occlusal surface after a clinical adjustment was compared to no adjustment (NA; design based on static occlusion), PSM (adjusted using PSM), and adjustment using a semi-adjustable articulator (SA) for the assessment of occlusal error. The root mean square (RMS; μm), average deviation value (±AVG; μm), and proportion inside the tolerance (in Tol; %) were calculated using the entire, subdivided occlusal surface and the out of tolerance area. Using a one-way ANOVA, the RMS and +AVG from the out of tolerance area showed a statistical difference between PSM (202.3 ± 39.8 for RMS, 173.1 ± 31.3 for +AVG) and NA (257.0 ± 73.9 for RMS, 210.9 ± 48.6 for +AVG). For the entire and subdivided occlusal surfaces, there were no significant differences. In the color-coded map analysis, PSM demonstrated a reduced occlusal error compared to NA. In conclusion, adjustment occlusal design using PSM is a simple and effective method for reducing occlusal errors that are difficult to identify in a current computer-aided design (CAD) workflow with static occlusion.

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