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

2020 ◽  
Vol 10 (21) ◽  
pp. 7895
Author(s):  
Runze Chen ◽  
Lixin Wang ◽  
Hongkai Zhang ◽  
Mengyao Cui ◽  
Min Guo

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.

Electronics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 745
Author(s):  
Runze Chen ◽  
Lixin Wang ◽  
Naixia Jiu ◽  
Hongkai Zhang ◽  
Min Guo

In this paper, a split-gate resurf stepped oxide with double floating electrodes (DFSGRSO) U-shape metal oxide semiconductor field-effect transistor (UMOSFET) is proposed. The floating electrodes are symmetrically distributed on both sides of the source electrode in the trench. The performance of the DFSGRSO UMOSFET with different size of floating electrodes is simulated and analyzed. The simulation results reveal that the floating electrodes can modulate the distribution of the electric field in the drift area, improving the performance of the device significantly. The breakdown voltage (BV) and figure of merit (FOM) of the DFSGRSO UMOSFET at optimal parameters are 23.6% and 53.1% higher than that of the conventional structure. In addition, the regulatory mechanism of the floating electrodes is analyzed. The electric field moves from the bottom of the trench to the middle of the drift area, which brings a new electric field peak. Therefore, the distribution of the electric field is more uniform for the DFSGRSO UMOSFET compared with the conventional structure.


Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 756
Author(s):  
Chia-Yuan Chen ◽  
Yun-Kai Lai ◽  
Kung-Yen Lee ◽  
Chih-Fang Huang ◽  
Shin-Yi Huang

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.


The choice of cost-effective method of anticorrosive protection of steel structures is an urgent and time consuming task, considering the significant number of protection ways, differing from each other in the complex of technological, physical, chemical and economic characteristics. To reduce the complexity of solving this problem, the author proposes a computational tool that can be considered as a subsystem of computer-aided design and used at the stage of variant and detailed design of steel structures. As a criterion of the effectiveness of the anti-corrosion protection method, the cost of the protective coating during the service life is accepted. The analysis of existing methods of steel protection against corrosion is performed, the possibility of their use for the protection of the most common steel structures is established, as well as the estimated period of effective operation of the coating. The developed computational tool makes it possible to choose the best method of protection of steel structures against corrosion, taking into account the operating conditions of the protected structure and the possibility of using a protective coating.


Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1775
Author(s):  
Jae-Min Sim ◽  
Myounggon Kang ◽  
Yun-Heub Song

In this paper, we investigated the cell-to-cell interference in scaled-down 3D NAND flash memory by using a Technology Computer-Aided Design (TCAD) simulation. The fundamental cause of cell-to-cell interference is that the electric field crowding point is changed by the programmed adjacent cell so that the electric field is not sufficiently directed to the channel surface. Therefore, the channel concentration of the selected cell is changed, leading to a Vth shift. Furthermore, this phenomenon occurs more severely when the selected cell is in an erased state rather than in a programmed state. In addition, it was confirmed that the cell-to-cell interference by the programmed WLn+1 is more severe than that of WLn−1 due to the degradation of the effective mobility effect. To solve this fundamental problem, a new read scheme is proposed. Through TCAD simulation, the cell-to-cell interference was alleviated with a bias having a ΔV of 1.5 V from Vread through an optimization process to have appropriate bias conditions in three ways that are suitable for each pattern. As a result, this scheme narrowed the Vth shift of 67.5% for erased cells and narrowed the Vth shift of 70% for programmed cells. The proposed scheme is one way to solve the cell-to-cell interference that may occur as the cell-to-cell distance decreases for a high stacked 3D NAND structure.


Author(s):  
Jonathan D Howard ◽  
Dominic Eggbeer ◽  
Peter Dorrington ◽  
Feras Korkees ◽  
Lorna H Tasker

The provision of wheelchair seating accessories, such as head supports, is often limited to the use of commercial products. Additive manufacturing has the potential to produce custom seating components, but there are very few examples of published work. This article reports a method of utilising 3D scanning, computer-aided design and additive manufacturing for the fabrication of a custom head support for a wheelchair. Three custom head supports, of the same shape, were manufactured in nylon using a continuous filament fabrication machine. The custom head supports were tested against an equivalent and widely used commercial head support using ISO 16840-3:2014. The head supports were statically loaded in two configurations, one modelling a posterior force on the inner rear surface and the other modelling a lateral force on the side. The posterior force resulted in failure of the supporting bracketry before the custom head support. A similar magnitude of forces was applied laterally for the custom and commercial head support. When the load was removed, the custom recovered to its original shape while the commercial sustained plastic deformation. The addition of a joint in the head support increased the maximum displacement, 128.6 mm compared to 71.7 mm, and the use of carbon fibre resulted in the head support sustaining a higher force at larger displacements, increase in 30 N. Based on the deformation and recovery characteristics, the results indicate that additive manufacturing could be an appropriate method to produce lighter weight, highly customised, cost-effective and safe head supports for wheelchair users.


2014 ◽  
Vol 597 ◽  
pp. 417-420
Author(s):  
Jeremy Zheng Li

The tooling and fixture play important roles in manufacturing and production. It affects both product quality and quantity. Better tooling and fixture can also promote cost-effective manufacturing process. This paper introduces a new type of universal clamping mechanism based on computer-aided 3D modeling, engineering structural analysis, and prototype testing. It can be applied to easily and reliably clamp different geometrical shape of work pieces per user requirements. This new clamping mechanism, with less moving components, can assist manufacturing industry for high speed production, easy part handling, precise clamping, and lower tooling cost. Keywords: Computer-aided design, automated production, 3D modeling, cost-effective, high speed manufacturing, engineering analysis, optimization, efficient;


1995 ◽  
Vol 117 (2) ◽  
pp. 199-204 ◽  
Author(s):  
J. R. Wagner

The cost effective design of antilock brake systems for automobiles requires the use of computer aided design and analysis techniques, as well as traditional invehicle testing. An important consideration in the simulation of the vehicle and brake dynamics is the generation of the shear forces and aligning torques at the tire/road interface. Frequently, experimental tire data gathered over a limited number of road surfaces is extrapolated to test antilock brake systems on a variety of roads. However, this approach may lead to problems in correlating the simulated system performance with actual vehicle tests. In this study, nonlinear programming strategies are applied to an analytical tire model to facilitate the selection of system variables. The formulation of an optimization problem to determine these variables permits the generation of shear forces which correspond fairly well with the empirical data. Simulation results are presented and discussed for five road surfaces to indicate the overall performance of this technique.


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