Characterization of AlGaN/GaN Cantilevers Fabricated with Deep-Release Techniques

2011 ◽  
Vol 483 ◽  
pp. 14-17
Author(s):  
Jian An Lv ◽  
Zhen Chuan Yang ◽  
Gui Zheng Yan ◽  
Yong Cai ◽  
Bao Shun Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stress Distribution ◽  
Bending Test ◽  
Output Current ◽  
Micro Raman Spectroscopy ◽  
Gan Hemt ◽  
Gan Hemts ◽  
Dry Etch ◽  
Mems Process

In this article, integrated AlGaN/GaN cantilevers on (111) silicon substrate are fabricated and characterized. The process started with AlGaN/GaN HEMTs fabrication followed by a series of dry-etch-only MEMS process. To characterize the residual stress distribution, Micro-Raman spectroscopy is used and the residual stress in suspended GaN cantilever is found ~ 90% lower after releasing. A type of micro-bending test is used to characterize the piezoresponse of AlGaN/GaN HEMT on the GaN cantilever. An output current modulation greater than 20% can be observed when the cantilever is vertically downward deflected ~ 30 µm.

Application of Indirect Laser Peening to SUS304 Stainless Steel

2014 ◽  
Vol 783-786 ◽  
pp. 2316-2321
Author(s):  
Hiroshi Kawakami ◽  
Akiyoshi Kondo ◽  
Muneharu Kutsuna ◽  
Kiyotaka Saito ◽  
Hiroki Inoue ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stress Distribution ◽  
Pulse Energy ◽  
Laser Power ◽  
Compressive Residual Stress ◽  
Residual Stress Distribution ◽  
Bending Test ◽  
Laser Peening

Indirect laser peening applied to the substrate of austenitic stainless steel with the sheet of similar material. Effects of indirect laser peening condition on the formation of the dimple and the residual stress were investigated in this paper. Shape of the dimple and distribution of the residual stress were measured by laser microscope and X-ray diffraction, respectively. It was observed by the microscope that clean substrate surface of as-received state kept after indirect laser peening because of protection by the sheet. However, fracture of sheet occurred slightly in high pulse energy condition. The diameter and the depth of the dimple by indirect laser peening increased with the increase of laser power. Efficiency of dimple formation decreased with the increase of pulse energy. Affective condition region of indirect laser peening with a combination between the substrate and the sheet of austenitic stainless steel may be limited below the laser power density of 10GW/cm2. It was confirmed that indirect laser peening induced compressive residual stress in the substrate. One of peak of compressive residual stress in residual stress distribution existed near the bottom of the dimple. Residual stress distribution which was produced by indirect laser peening may affect change of quasi bending modulus which was obtained by three-point bending test.

Characterization of the three-dimensional residual stress distribution in SiC bulk crystals by neutron diffraction

CrystEngComm ◽  
2017 ◽  
Vol 19 (43) ◽  
pp. 6527-6532 ◽  
Author(s):  
Xuejian Xie ◽  
Xiaobo Hu ◽  
Xiufang Chen ◽  
Fafu Liu ◽  
Xianglong Yang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Neutron Diffraction ◽  
Three Dimensional ◽  
Diffraction Method ◽  
Residual Stress Distribution ◽  
Bulk Crystals ◽  
First Time ◽  
Neutron Diffraction Method

The neutron diffraction method was adopted to study the three-dimensional residual stress distribution in SiC bulk crystals for the first time.

Experimental and numerical analysis of the residual stress distribution in a three-point bending test of a TRIP sheet by using ESPI

2020 ◽  
Vol 42 (10) ◽  
Author(s):  
Alan E. Díaz-Mendoza ◽  
Gustavo Capilla-González ◽  
Israel Martínez-Ramírez ◽  
Miguel E. Gutiérrez-Rivera ◽  
David Díaz-Infante ◽  
...  
Keyword(s):  
Residual Stress ◽  
Numerical Analysis ◽  
Stress Distribution ◽  
Residual Stress Distribution ◽  
Bending Test ◽  
Three Point Bending

Correlation of Stress in Silicon Carbide Crystal and Frequency Shift in Micro-Raman Spectroscopy

2014 ◽  
Vol 1693 ◽  
Author(s):  
N. Sugiyama ◽  
M. Yamada ◽  
Y. Urakami ◽  
M. Kobayashi ◽  
T. Masuda ◽  
...  
Keyword(s):  
Residual Stress ◽  
Silicon Carbide ◽  
Raman Spectroscopy ◽  
Frequency Shift ◽  
Uniaxial Stress ◽  
Bending Test ◽  
Raman Shift ◽  
Micro Raman Spectroscopy ◽  
Four Point Bending

ABSTRACTThe correlation of stress in Silicon Carbide (SiC) crystal and frequency shift in micro- Raman spectroscopy was determined by an experimental method. We applied uniaxial stress to 4H- and 6H-SiC single crystal square bar specimen shaped with (0001) and (11-20) faces by four point bending test, under measuring the frequency shift in micro-Raman spectroscopy. The results revealed that the linearity coefficients between stress and Raman shift were -1.96 cm-1/GPa for FTO(2/4)E2 on 4H-SiC (0001) face, -2.08 cm-1/GPa for FTO(2/4)E2 on 4H-SiC (11-20) face and -2.70 cm-1/GPa for FTO(2/6)E2 on 6H-SiC (0001) face. Determination of these coefficients has made it possible to evaluate the residual stress in SiC crystal quantitatively by micro-Raman spectroscopy. We evaluated the residual stress in SiC substrate that was grown in our laboratory by utilizing the results obtained in this study. The result of estimation indicated that the SiC substrate with a diameter of 6 inch remained residual stress as low as ±15 MPa.

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