99.9% BPD Free 4H-SiC Epitaxial Layer with Precisely Controlled Doping upon 3 x 150 mm Hot-Wall CVD

Epitaxial growth of 4H-SiC on 150 mm wafers has been investigated using experimental results and numerical simulations toward the goal of BPDs reduction and doping uniformity control in the epitaxial layer. We have reported analyses of the temperature distribution dependence of the doping uniformity and BPDs propagations on the 3 x 150 mm multi-wafer CVD epitaxial growth. By optimizing epitaxial growth conditions, we have demonstrated an excellent doping and thickness uniformity and a 99.9% BPD free region, simultaneously.

Download Full-text

Extensive 99% Killer Defect Free 4H-SiC Epitaxial Layer toward High Current Large Chip Devices

Materials Science Forum ◽

10.4028/www.scientific.net/msf.963.105 ◽

2019 ◽

Vol 963 ◽

pp. 105-108

Author(s):

Keiji Wada ◽

Takaya Miyase ◽

Hironori Itoh ◽

Tsutomu Hori ◽

Hideyuki Doi ◽

...

Keyword(s):

Epitaxial Growth ◽

Epitaxial Layer ◽

Defect Density ◽

Growth Conditions ◽

High Current ◽

Growth Processes ◽

Thickness Uniformity

Epitaxial growth of 4H-SiC on 150 mm wafers using 3 x 150 mm multi-wafer CVD has been investigated to realize extremely low defect density on the epitaxial layer in order to achieve stable fabrication of high current devices with large die size. By optimizing the epitaxial growth conditions as well as the improved procedures for the inside the furnace to remain cleaned stably for cumulative growth processes, we have demonstrated an extensive 99% defect free epitaxial inlayer in a 5 mm x 5 mm block evaluation which is having excellent doping and thickness uniformity simultaneously.

Download Full-text

Control of the Surface Morphology on Low Off Angled 4H-SiC Homoepitaxal Growth

Materials Science Forum ◽

10.4028/www.scientific.net/msf.615-617.113 ◽

2009 ◽

Vol 615-617 ◽

pp. 113-116 ◽

Cited By ~ 8

Author(s):

Kazutoshi Kojima ◽

Hajime Okumura ◽

Kazuo Arai

Keyword(s):

Surface Morphology ◽

Epitaxial Growth ◽

Epitaxial Layer ◽

Flow Rate ◽

Growth Conditions ◽

Layer Surface ◽

Specular Surface ◽

Homoepitaxial Growth ◽

Angle Difference ◽

The Face

We have carried out detailed investigations on the influence of the growth conditions and the wafer off angle on the surface morphology of low off angle homoepitaxial growth. We found triangular features to be also serious problems on a 4 degree off 4H-SiC Si-face epitaxial layer surface. The control of the C/Si ratio by controlling the SiH4 flow rate is effective in suppressing the triangular features on 4 degree off Si-face homoepitaxial layer. As regards epitaxial growth on a vicinal off-axis substrate, the small off angle difference of a tenth part of a degree has an influence on the surface morphology of the epitaxial layer. This tendency depends on the face polarity and a C-face can be obtained that has a specular surface with a lower vicinal off angle than a Si-face. By controlling this off angle, a specular surface morphology without a bunched step structure could be obtained on a vicinal off angle 4H-SiC Si-face.

Download Full-text

Investigation of In-Grown Dislocations in 4H-SiC Epitaxial Layers

Materials Science Forum ◽

10.4028/www.scientific.net/msf.527-529.147 ◽

2006 ◽

Vol 527-529 ◽

pp. 147-152 ◽

Cited By ~ 5

Author(s):

Kazutoshi Kojima ◽

Tomohisa Kato ◽

Satoshi Kuroda ◽

Hajime Okumura ◽

Kazuo Arai

Keyword(s):

Epitaxial Growth ◽

Epitaxial Layer ◽

Basal Plane ◽

Growth Conditions ◽

Epitaxial Layers ◽

Etch Pit Density ◽

High Conversion Efficiency ◽

Etch Pit ◽

Edge Dislocations

We have investigated the generation of new dislocations during the epitaxial growth of 4H-SiC layers. Dislocations were mainly propagated from the substrate into the epitaxial layer. However, it was found that some amount of new threading edge dislocations (TEDs) and basal plane dislocations (BPDs) were generated during the epitaxial growth. The generation of those dislocations appeared to depend on the in-situ H2 etching conditions, not the epitaxial growth conditions. By optimizing in-situ H2 etching condition, we were able to effectively suppress the generation of new dislocations during epitaxial growth, and obtain 4H-SiC epitaxial layers which have the equivalent etch pit density (EPD) to the substrates. Our additional investigation of the conversion of BPDs to TEDs revealed that its efficiency similarly depends on in-situ H2 etching. We were able to obtain a high conversion efficiency of 97 % by optimizing the in-situ H2 etching conditions before epitaxial growth.

Download Full-text

Dependence of 4H-SiC Epitaxial Layer Quality on Growth Conditions with Wafer Size Corresponding to 150 mm

MRS Proceedings ◽

10.1557/opl.2012.1140 ◽

2012 ◽

Vol 1433 ◽

Cited By ~ 5

Author(s):

Chiaki Kudou ◽

Kentaro Tamura ◽

Takashi Aigo ◽

Wataru Ito ◽

Johji Nishio ◽

...

Keyword(s):

Surface Morphology ◽

Carrier Concentration ◽

Epitaxial Layer ◽

Radial Direction ◽

Defect Density ◽

Growth Conditions ◽

Thickness Uniformity ◽

Homoepitaxial Growth ◽

Major Parameter ◽

Wafer Size

ABSTRACTHomoepitaxial growth on 4H-SiC Si-face substrates with sizes corresponding to 150 mm was carried out. The influence of growth conditions for uniformity and epitaxial defect density was investigated. A 150 mm size was realized by using two 76.2 mm wafers lined up in a radial direction. C/Si ratio is found to be a major parameter for controlling triangular defect density and the generation of step bunching. As a result, the surface morphology without bunched step structure and the triangular defect density with 0.5 cm−2 were obtained by decreasing C/Si ratio to 1.0 on the size corresponding to 150 mm. Under this condition, good carrier concentration and thickness uniformity of σ/mean =15.2 % and 1.7 % could be obtained.

Download Full-text

Properties of disordered sphere packings I. Geometric structure: Statistical model, numerical simulations and experimental results

Powder Technology ◽

10.1016/0032-5910(86)80018-3 ◽

1986 ◽

Vol 46 (2-3) ◽

pp. 121-131 ◽

Cited By ~ 50

Author(s):

L. Oger ◽

J.P. Troadec ◽

D. Bideau ◽

J.A. Dodds ◽

M.J. Powell

Keyword(s):

Statistical Model ◽

Numerical Simulations ◽

Geometric Structure ◽

Experimental Results ◽

Sphere Packings

Download Full-text

Additive manufacturing of pure copper: From numerical simulations to experimental results

Laser 3D Manufacturing VIII ◽

10.1117/12.2578320 ◽

2021 ◽

Author(s):

Hagen Kohl ◽

Lisa Schade ◽

Gabor Matthäus ◽

Tobias Ullsperger ◽

Burak Yürekli ◽

...

Keyword(s):

Additive Manufacturing ◽

Numerical Simulations ◽

Pure Copper ◽

Experimental Results

Download Full-text

Effect of Ramp Angle on the Anti-Loosening Ability of Wedge Self-Locking Nuts Under Vibration

Journal of Mechanical Design ◽

10.1115/1.4040167 ◽

2018 ◽

Vol 140 (7) ◽

Cited By ~ 5

Author(s):

Jianhua Liu ◽

Hao Gong ◽

Xiaoyu Ding

Keyword(s):

Finite Element ◽

Numerical Simulations ◽

Production Technology ◽

Material Properties ◽

Threshold Value ◽

Commercial Production ◽

Experimental Results ◽

Fe Method ◽

Transversal Vibration

Recently, the wedge self-locking nut, a special anti-loosening product, is receiving more attention because of its excellent reliability in preventing loosening failure under vibration conditions. The key characteristic of a wedge self-locking nut is the special wedge ramp at the root of the thread. In this work, the effect of ramp angle on the anti-loosening ability of wedge self-locking nuts was studied systematically based on numerical simulations and experiments. Wedge self-locking nuts with nine ramp angles (10 deg, 15 deg, 20 deg, 25 deg, 30 deg, 35 deg, 40 deg, 45 deg, and 50 deg) were modeled using a finite element (FE) method, and manufactured using commercial production technology. Their anti-loosening abilities under transversal vibration conditions were analyzed based on numerical and experimental results. It was found that there is a threshold value of the initial preload below which the wedge self-locking nuts would lose their anti-loosening ability. This threshold value of initial preload was then proposed for use as a criterion to evaluate the anti-loosening ability of wedge self-locking nuts quantitatively and to determine the optimal ramp angle. Based on this criterion, it was demonstrated, numerically and experimentally, that a 30 deg wedge ramp resulted in the best anti-loosening ability among nine ramp angles studied. The significance of this study is that it provides an effective method to evaluate the anti-loosening ability of wedge self-locking nuts quantitatively, and determined the optimal ramp angle in terms of anti-loosening ability. The proposed method can also be used to optimize other parameters, such as the material properties and other dimensions, to guarantee the best anti-loosening ability of wedge self-locking nuts.

Download Full-text

Numerical Simulations of V-Shaped Plates Subjected to Blast Loadings: A Validation Study

Modern Applied Science ◽

10.5539/mas.v10n11p203 ◽

2016 ◽

Vol 10 (11) ◽

pp. 203

Author(s):

Mohd Zaid Othman ◽

Qasim H. Shah ◽

Muhammad Akram Muhammad Khan ◽

Tan Kean Sheng ◽

M. A. Yahaya ◽

...

Keyword(s):

Numerical Simulation ◽

Numerical Simulations ◽

Variable Mass ◽

Blast Loading ◽

Experimental Results ◽

Average Difference ◽

Simulation Results ◽

Blast Loadings ◽

Carrier Vehicle ◽

Good Agreement

A series of numerical simulations utilizing LS-DYNA was performed to determine the mid-point deformations of V-shaped plates due to blast loading. The numerical simulation results were then compared with experimental results from published literature. The V-shaped plate is made of DOMEX 700 and is used underneath an armour personal carrier vehicle as an anti-tank mine to mitigate the effects of explosion from landmines in a battlefield. The performed numerical simulations of blast loading of V-shaped plates consisted of various angles i.e. 60°, 90°, 120°, 150° and 180°; variable mass of explosives located at the central mid-point of the V-shaped vertex with various stand-off distances. It could be seen that the numerical simulations produced good agreement with the experimental results where the average difference was about 26.6%.

Download Full-text