Low‐Energy UV Ultrafast Laser Controlled Lift‐Off for High‐Quality Flexible GaN‐Based Device

2022 ◽  
pp. 2111920
Weigao Sun ◽  
Lingfei Ji ◽  
Zhenyuan Lin ◽  
Jincan Zheng ◽  
Zhiyong Wang ◽  
1989 ◽  
Vol 145 ◽  
H. Temkin ◽  
L. R. Harriott ◽  
J. Weiner ◽  
R. A. Hamm ◽  
M. B. Panish

AbstractWe demonstrate a vacuum lithography process which uses a finely focused Ga ion beam to write the pattern which is then transferred to the InP pattern by low energy dry etching. Surface steps on the order of 1000-2000A in height, and lateral resolution limited only by size of the ion beam, can be efficiently prepared using moderate Ga ion fluences. The surfaces prepared by this process are damage free and suitable for epitaxial overgrowth. GaInAs/InP heterostructures grown on in-situ patterned substrates show excellent morphology and high luminescence efficiency.

2017 ◽  
Vol 897 ◽  
pp. 375-378 ◽  
Satoshi Torimi ◽  
Koji Ashida ◽  
Norihito Yabuki ◽  
Masato Shinohara ◽  
Takuya Sakaguchi ◽  

As a new thinning and surface planarizing process of Silicon Carbide (SiC) wafer, we propose the completely thermal-chemical etching process; Si-vapor etching (Si-VE) technology. In this work, the effects of mechanical strength and surface step-terrace structure by Si-VE are investigated on the 4° off-axis 4H-SiC (0001) Si-face substrates. The indentation hardness of Si-VE surface is superior to the conventional chemo-mechanical polishing (CMP) surface even after epitaxial growth. The transverse strength of thinned Si-VE substrate is also superior to the conventional mechanically ground substrate. The surface step-terrace structures are observed by the low energy electron channeling contrast (LE-ECC) imaging technique. The latent scratch causes bunched step lines (BSLs) with various inhomogeneous step morphologies only on the CMP surface.

Pierre Pennarun ◽  
Carole Rossi ◽  
Daniel Esteve ◽  
Denis Lagrange

A new concept of one shot micro-switches is proposed. Different switches have been developed to achieve either ON-OFF switching or OFF-ON switching. They are based on electrothermal mechanisms. ON-OFF switching consists in breaking an electrical connection using energetic material or low melting point metal like aluminum. OFF-ON switching consists in micro-soldering locally two electrical connections. Switches commute with a few hundred of mW and do not need energy to stay in the stable OFF or ON state. These switches are particularly adapted to spatial redundancy applications that need high quality contact and reliable commutation even after long time storage. The fabrication process of these switches is based on classic MEMS technology steps (LPCVD, PECVD, copper electrodeposition, lift-off and plasma etching) and is IC compatible. Fabrication yield reaches 99%.

2005 ◽  
Vol 475-479 ◽  
pp. 3605-3610 ◽  
S.G. Wang ◽  
P.J. Sellin ◽  
Q. Zhang ◽  
Fan Xiu Lu ◽  
Wei Zhong Tang ◽  

In this study, X-ray detectors with coplanar metal-semiconductor-metal structure, were fabricated employing high quality chemical vapour deposited (CVD) diamond film grown by a direct current arc jet plasma system. In which the electrical contacts with dimension of 25 µm in width with a 25 µm inter-electrode spacing, were patterned on the growth side of the diamond film using lift-off technology. The performance of the fabricated detectors was evaluated by steady-state X-ray illumination. The photoconductivity of the diamond detectors was found to linearly increase with increase in the X-ray photon flux. This demonstrates that high quality CVD diamond can be used for X-ray detectors.

2020 ◽  
Vol 5 (1) ◽  
pp. e000560
Vera Pedersen ◽  
Alina Lampart ◽  
Roland Bingisser ◽  
Christian Hans Nickel

BackgroundOlder individuals sustaining low-energy falls (LEF) and presenting to the emergency department (ED) demand straightforward diagnostic measures for injury detection. Plain radiography (XR) series for diagnosis of fall-related injuries are standard of care, but frequently subsequent CT examination is required for diagnostic assurance. A systematic database search of diagnostic accuracy of XR for detection of fractures in older LEF patients was performed.MethodsWe searched PubMed, Embase, Cochrane Library, WHO International Clinical Trial Platform, and Clinical trials.gov databases from inception to January 2020 for studies including older patients (≥65 years) with LEF and obtaining CT examination and XR of the skeleton in an ED setting.ResultsFrom 8944 references screened, 11 studies met the criteria for inclusion. Performance of XR for detection of fractures of the pelvic ring and hip was analyzed in nine studies, two studies investigated XR performance to detect rib fractures, and two studies compared diagnostic accuracy of thoracolumbar spine XR. Sensitivity estimates ranged from 10% to 58% and specificity estimates from 55% to 100%. Clinical and statistical heterogeneity was significant among included studies, with an overall considerable risk of bias.DiscussionHigh-quality evidence on accurate imaging strategies in older patients with LEF is lacking to date. XR is missing a reasonable amount of fractures of the pelvic ring, rib cage, and thoracic and lumbar spine. However, the utility of first-line CT imaging and the benefit of diagnosing every fracture is unknown, demanding high-quality prospective trials considering patient-oriented outcome as well.

2014 ◽  
Vol 54 (9) ◽  
pp. 1190 ◽  
Ilias Kyriazakis

A reduction in voluntary food intake is a common feature of infection with pathogens and is frequently referred to as pathogen-induced anorexia. Anorexia has been previously viewed either as an unavoidable consequence of infection or as an animal strategy that enables them to cope with the consequences of infection. Both approaches lead to certain expectations as far as the characteristics of anorexia are concerned. By linking anorexia to host immune response one should be able to make predictions about when and for how long anorexia would occur. By appreciating what an infected animal is trying to achieve through its feeding behaviour, one would be able to make predictions about the extent of anorexia on different quality foods. The thesis of the paper is that these approaches should no longer be viewed as mutually exclusive, but, by combining them, one should be able to make pathogen-induced anorexia more predictable. This is done in the development of a model that aims to predict the food intake of grazing sheep exposed to an abomasal parasite. The predictions of the model are consistent with the features and consequences of parasite-induced anorexia of sheep given access to moderate and high quality foods. However, there is a degree of uncertainty about the validity of predictions made by the model on anorexia seen on poor quality foods of low energy content. This is not a deficiency of the model developed but can be attributed to the lack of appropriate experiments against which model predictions can be tested.

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