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Nickel Foam as a Substrate for III-nitride Nanowire Growth
- Michael A. Mastro, Neeraj Nepal, Fritz Kub, Jennifer K. Hite, Jihyun Kim, Charles R. Eddy, Jr.
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- Journal:
- MRS Online Proceedings Library Archive / Volume 1538 / 2013
- Published online by Cambridge University Press:
- 05 April 2013, pp. 311-316
- Print publication:
- 2013
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This article presents the use of flexible metal foam substrates for the growth of III-nitride nanowire light emitters to tackle the inherent limitations of thin-film light emitting diodes as well as fabrication and application issues of traditional substrates. A dense packing of gallium nitride nanowires were grown on a nickel foam substrate. The nanowires grew predominantly along the a-plane direction, normal to the local surface of the nickel foam. Strong luminescence was observed from undoped GaN and InGaN quantum well light emitting diode nanowires.
Contributors
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- By Aakash Agarwala, Linda S. Aglio, Rae M. Allain, Paul D. Allen, Houman Amirfarzan, Yasodananda Kumar Areti, Amit Asopa, Edwin G. Avery, Patricia R. Bachiller, Angela M. Bader, Rana Badr, Sibinka Bajic, David J. Baker, Sheila R. Barnett, Rena Beckerly, Lorenzo Berra, Walter Bethune, Sascha S. Beutler, Tarun Bhalla, Edward A. Bittner, Jonathan D. Bloom, Alina V. Bodas, Lina M. Bolanos-Diaz, Ruma R. Bose, Jan Boublik, John P. Broadnax, Jason C. Brookman, Meredith R. Brooks, Roland Brusseau, Ethan O. Bryson, Linda A. Bulich, Kenji Butterfield, William R. Camann, Denise M. Chan, Theresa S. Chang, Jonathan E. Charnin, Mark Chrostowski, Fred Cobey, Adam B. Collins, Mercedes A. Concepcion, Christopher W. Connor, Bronwyn Cooper, Jeffrey B. Cooper, Martha Cordoba-Amorocho, Stephen B. Corn, Darin J. Correll, Gregory J. Crosby, Lisa J. Crossley, Deborah J. Culley, Tomas Cvrk, Michael N. D'Ambra, Michael Decker, Daniel F. Dedrick, Mark Dershwitz, Francis X. Dillon, Pradeep Dinakar, Alimorad G. Djalali, D. John Doyle, Lambertus Drop, Ian F. Dunn, Theodore E. Dushane, Sunil Eappen, Thomas Edrich, Jesse M. Ehrenfeld, Jason M. Erlich, Lucinda L. Everett, Elliott S. Farber, Khaldoun Faris, Eddy M. Feliz, Massimo Ferrigno, Richard S. Field, Michael G. Fitzsimons, Hugh L. Flanagan Jr., Vladimir Formanek, Amanda A. Fox, John A. Fox, Gyorgy Frendl, Tanja S. Frey, Samuel M. Galvagno Jr., Edward R. Garcia, Jonathan D. Gates, Cosmin Gauran, Brian J. Gelfand, Simon Gelman, Alexander C. Gerhart, Peter Gerner, Omid Ghalambor, Christopher J. Gilligan, Christian D. Gonzalez, Noah E. Gordon, William B. Gormley, Thomas J. Graetz, Wendy L. Gross, Amit Gupta, James P. Hardy, Seetharaman Hariharan, Miriam Harnett, Philip M. Hartigan, Joaquim M. Havens, Bishr Haydar, Stephen O. Heard, James L. Helstrom, David L. Hepner, McCallum R. Hoyt, Robert N. Jamison, Karinne Jervis, Stephanie B. Jones, Swaminathan Karthik, Richard M. Kaufman, Shubjeet Kaur, Lee A. Kearse Jr., John C. Keel, Scott D. Kelley, Albert H. Kim, Amy L. Kim, Grace Y. Kim, Robert J. Klickovich, Robert M. Knapp, Bhavani S. Kodali, Rahul Koka, Alina Lazar, Laura H. Leduc, Stanley Leeson, Lisa R. Leffert, Scott A. LeGrand, Patricio Leyton, J. Lance Lichtor, John Lin, Alvaro A. Macias, Karan Madan, Sohail K. Mahboobi, Devi Mahendran, Christine Mai, Sayeed Malek, S. Rao Mallampati, Thomas J. Mancuso, Ramon Martin, Matthew C. Martinez, J. A. Jeevendra Martyn, Kai Matthes, Tommaso Mauri, Mary Ellen McCann, Shannon S. McKenna, Dennis J. McNicholl, Abdel-Kader Mehio, Thor C. Milland, Tonya L. K. Miller, John D. Mitchell, K. Annette Mizuguchi, Naila Moghul, David R. Moss, Ross J. Musumeci, Naveen Nathan, Ju-Mei Ng, Liem C. Nguyen, Ervant Nishanian, Martina Nowak, Ala Nozari, Michael Nurok, Arti Ori, Rafael A. Ortega, Amy J. Ortman, David Oxman, Arvind Palanisamy, Carlo Pancaro, Lisbeth Lopez Pappas, Benjamin Parish, Samuel Park, Deborah S. Pederson, Beverly K. Philip, James H. Philip, Silvia Pivi, Stephen D. Pratt, Douglas E. Raines, Stephen L. Ratcliff, James P. Rathmell, J. Taylor Reed, Elizabeth M. Rickerson, Selwyn O. Rogers Jr., Thomas M. Romanelli, William H. Rosenblatt, Carl E. Rosow, Edgar L. Ross, J. Victor Ryckman, Mônica M. Sá Rêgo, Nicholas Sadovnikoff, Warren S. Sandberg, Annette Y. Schure, B. Scott Segal, Navil F. Sethna, Swapneel K. Shah, Shaheen F. Shaikh, Fred E. Shapiro, Torin D. Shear, Prem S. Shekar, Stanton K. Shernan, Naomi Shimizu, Douglas C. Shook, Kamal K. Sikka, Pankaj K. Sikka, David A. Silver, Jeffrey H. Silverstein, Emily A. Singer, Ken Solt, Spiro G. Spanakis, Wolfgang Steudel, Matthias Stopfkuchen-Evans, Michael P. Storey, Gary R. Strichartz, Balachundhar Subramaniam, Wariya Sukhupragarn, John Summers, Shine Sun, Eswar Sundar, Sugantha Sundar, Neelakantan Sunder, Faraz Syed, Usha B. Tedrow, Nelson L. Thaemert, George P. Topulos, Lawrence C. Tsen, Richard D. Urman, Charles A. Vacanti, Francis X. Vacanti, Joshua C. Vacanti, Assia Valovska, Ivan T. Valovski, Mary Ann Vann, Susan Vassallo, Anasuya Vasudevan, Kamen V. Vlassakov, Gian Paolo Volpato, Essi M. Vulli, J. Matthias Walz, Jingping Wang, James F. Watkins, Maxwell Weinmann, Sharon L. Wetherall, Mallory Williams, Sarah H. Wiser, Zhiling Xiong, Warren M. Zapol, Jie Zhou
- Edited by Charles Vacanti, Scott Segal, Pankaj Sikka, Richard Urman
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- Book:
- Essential Clinical Anesthesia
- Published online:
- 05 January 2012
- Print publication:
- 11 July 2011, pp xv-xxviii
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DISCRIMINATION-RELATED STRESS, BLOOD PRESSURE AND EPSTEIN-BARR VIRUS ANTIBODIES AMONG LATIN AMERICAN IMMIGRANTS IN OREGON, US
- HEATHER H. McCLURE, CHARLES R. MARTINEZ, Jr, J. JOSH SNODGRASS, J. MARK EDDY, ROBERTO A. JIMÉNEZ, LAURA E. ISIORDIA, THOMAS W. McDADE
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- Journal:
- Journal of Biosocial Science / Volume 42 / Issue 4 / July 2010
- Published online by Cambridge University Press:
- 24 February 2010, pp. 433-461
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Perceived discrimination has been linked to poor health outcomes among ethnic and racial minorities in the United States, though the relationship of discrimination-related stress to immigrant health is not well understood. This article reports findings from a preliminary study that examined blood pressure and Epstein-Barr virus antibody levels in relation to self-reported indicators of stress, acculturation and social support among 79 adult immigrant Latino farm workers in Oregon, US. Findings show that increases in discrimination-related stress predicted elevated systolic blood pressure (SBP) and Epstein-Barr virus antibody levels among male participants. Though female participants reported similar levels of discrimination stress, this perceived stress was not reflected in biological measures. Among women, greater English language engagement was linked to higher SBP, and more years in the US was associated with higher diastolic blood pressure. Study results suggest that male and female immigrants' physiological responses to stress may be influenced in distinctive ways by processes of adjustment to life in the US. If replicated, the finding that discrimination stress predicts elevated SBP may have clinical and public health implications given that elevated SBP is an established risk factor for cardiovascular disease.
Recent Results From Epitaxial Growth on Step Free 4H-SiC Mesas
- Philip G. Neudeck, Andrew J. Trunek, David J. Spry, J. Anthony Powell, Hui Du, Marek Skowronski, Nabil D. Bassim, Michael A. Mastro, Mark E. Twigg, Ronald T. Holm, Richard L. Henry, Charles R. Eddy, Jr.
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- Journal:
- MRS Online Proceedings Library Archive / Volume 911 / 2006
- Published online by Cambridge University Press:
- 01 February 2011, 0911-B08-03
- Print publication:
- 2006
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This paper updates recent progress made in growth, characterization, and understanding of high quality homoepitaxial and heteroepitaxial films grown on step-free 4H-SiC mesas. First, we report initial achievement of step-free 4H-SiC surfaces with carbon-face surface polarity. Next, we will describe further observations of how step-free 4H-SiC thin lateral cantilever evolution is significantly impacted by crystal faceting behavior that imposes non-uniform film thickness on cantilever undersides. Finally, recent investigations of in-plane lattice constant mismatch strain relief mechanisms observed for heteroepitaxial growth of 3C-SiC as well as 2H-AlN/GaN heterofilms on step-free 4H-SiC mesas will be reviewed. In both cases, the complete elimination of atomic heterointerface steps on the mesa structure enables uniquely well-ordered misfit dislocation arrays to form near the heterointerfaces with remarkable lack of dislocations threading vertically into the heteroepilayers. In the case of 3C-SiC heterofilms, it has been proposed that dislocation half-loops nucleate at mesa edges and glide laterally along the step-free 3C/4H interfaces. In contrast, 3C-SiC and 2H-AlN/GaN heterofilms grown on 4H-SiC mesas with steps exhibit highly disordered interface misfit dislocation structure coupled with 100X greater density of dislocations threading through the thickness of the heteroepilayers. These results indicate that the presence of steps at the heteroepitaxial interface (i.e., on the initial heteroepitaxial nucleation surface) plays a highly important role in the defect structure, quality, and relaxation mechanisms of single-crystal heteroepitaxial films.
Growth Evolution of Gallium Nitride Films on Stepped and Step-Free SiC Surfaces
- Charles R. Eddy, Jr, James C. Culbertson, Nabil D. Bassim, Mark E. Twigg, Ronald T. Holm, Robert E. Stahlbush, Richard L. Henry, Philip G. Neudeck, Andrew J. Trunek, J. Anthony Powell
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- Journal:
- MRS Online Proceedings Library Archive / Volume 798 / 2003
- Published online by Cambridge University Press:
- 01 February 2011, Y3.7
- Print publication:
- 2003
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Silicon carbide (SiC) is rapidly becoming the substrate of choice for the development of high frequency and high power electronic devices employing the III-V nitride family of materials. This heteroepitaxial growth system continues to receive considerable attention, as materials issues remain the fundamental limiters to device performance. The heteroepitaxial growth of gallium nitride (GaN) thin films on stepped and step-free 4H SiC surfaces is reported. Step-free SiC surfaces are created by mesa patterning of a SiC wafer and subsequent epitaxial growth in a process described previously. This process results in a collection of both step-free and stepped surfaces on a given sample. We have employed an established metalorganic chemical vapor deposition process to grow first a thin (1200Å) aluminum nitride (AlN) nucleation layer and then a 2 μm thick GaN thin film. We have interrupted growth at various stages of AlN and GaN growth to evaluate the growth evolution using atomic force microscopy (AFM). The results show marked differences in the manner in which the initial AlN layer deposits. Nucleation is random with elongated grains on step-free SiC surfaces, while stepped surfaces have round nuclei of uniform dimensions and a high degree of spatial correlation with the nuclei arranged in rows. These differences diminish as the AlN layer approaches the desired thickness. Growth of the GaN epilayer is also markedly different on the two types of surfaces with step-free surfaces leading to random and low density nucleation of crystallites that remain as single grains for long growth times, whereas the stepped surfaces have large numbers nuclei that rapidly grow laterally. Cross-sectional transmission electron microscopy (TEM) reveals that grain sizes are 2–3X larger on step-free surfaces.
Etch Processing of III-V Nitrides
- Charles R. Eddy, Jr.
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- Journal:
- Materials Research Society Internet Journal of Nitride Semiconductor Research / Volume 4 / Issue S1 / 1999
- Published online by Cambridge University Press:
- 13 June 2014, pp. 902-913
- Print publication:
- 1999
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As III-V nitride devices advance in technological importance, a fundamental understanding of device processing techniques becomes essential. Recent works have exposed various aspects of etch processes. The most recent advances and the greatest remaining challenges in the etching of GaN, AlN, and InN are reviewed. A more detailed presentation is given with respect to GaN high density plasma etching. In particular, the results of parametric and fundamental studies of GaN etching in a high density plasma are described. The effect of ion energy and mass on surface electronic properties is reported. Experimental results identify preferential sputtering as the leading cause of observed surface non-stoichiometry. This mechanism provides excellent surfaces for ohmic contacts to n-type GaN, but presents a major obstacle for Schottky contacts or ohmic contacts to p-type GaN. Chlorine-based discharges minimize this stoichiometry problem by improving the rate of gallium removal from the surface. In an effort to better understand the high density plasma etching process for GaN, in-situ mass spectrometry is employed to study the chlorine-based high density plasma etching process. Gallium chloride mass peaks were monitored in a highly surface sensitive geometry as a function of microwave power (ion flux), total pressure (neutral flux), and ion energy. Microwave power and pressure dependencies clearly demonstrate the importance of reactive ions in the etching of wide band gap materials. The ion energy dependence demonstrates the importance of adequate ion energy to promote a reasonable etch rate (≥100-150 eV). The benefits of ion-assisted chemical etching are diminished for ion energies in excess of 350 V, placing an upper limit to the useful ion energy range for etching GaN. The impact of these results on device processing will be discussed and future needs identified.
Etch Processing of III-V Nitrides
- Charles R. Eddy, Jr
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- Journal:
- MRS Online Proceedings Library Archive / Volume 537 / 1998
- Published online by Cambridge University Press:
- 10 February 2011, G10.5
- Print publication:
- 1998
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As III-V nitride devices advance in technological importance, a fundamental understanding of device processing techniques becomes essential. Recent works have exposed various aspects of etch processes. The most recent advances and the greatest remaining challenges in the etching of GaN, AIN, and InN are reviewed. A more detailed presentation is given with respect to GaN high density plasma etching. In particular, the results of parametric and fundamental studies of GaN etching in a high density plasma are described. The effect of ion energy and mass on surface electronic properties is reported. Experimental results identify preferential sputtering as the leading cause of observed surface non-stoichiometry. This mechanism provides excellent surfaces for ohmic contacts to n-type GaN, but presents a major obstacle for Schottky contacts or ohmic contacts to p-type GaN. Chlorine-based discharges minimize this stoichiometry problem by improving the rate of gallium removal from the surface. In an effort to better understand the high density plasma etching process for GaN, in-situ mass spectrometry is employed to study the chlorine-based high density plasma etching process. Gallium chloride mass peaks were monitored in a highly surface sensitive geometry as a function of microwave power (ion flux), total pressure (neutral flux), and ion energy. Microwave power and pressure dependencies clearly demonstrate the importance of reactive ions in the etching of wide band gap materials. The ion energy dependence demonstrates the importance of adequate ion energy to promote a reasonable etch rate (≥ 100-150 eV). The benefits of ion-assisted chemical etching are diminished for ion energies in excess of 350 V, placing an upper limit to the useful ion energy range for etching GaN. The impact of these results on device processing will be discussed and future needs identified.
Reactive-Ion-Etching of 100nm Linewidth Tungsten Features Using SF6:H2 and a Cr-Liftoff Mask
- Loretita M. Shirey, Kelly W. Foster, William Chu, John Kosakowski, Kee Woo Rhee, Charles Eddy, Jr., Doewon Park, I. Peter Isaacson, Daniel Mccarthy, Christie R. K. Marrian, Martin C. Peckerar, Elizabeth A. Dobisz
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- Journal:
- MRS Online Proceedings Library Archive / Volume 324 / 1993
- Published online by Cambridge University Press:
- 22 February 2011, 487
- Print publication:
- 1993
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Reactive ion etching of features down to 100 nm in linewidth in tungsten has been studied using an SF6 based chemistry. The studies were carried out in a PlasmaTherm 500 etcher operated at low pressure (2 mTorr) and power (100 mWatts/cm2). Key processing parameters have been identified to achieve the resolution and aspect ratio required for high contrast x-ray masks. The critical parameters include sample temperature, gas dilution and end point detection. However, even with all of these parameters optimized, additional sidewall passivation is required to obtain the necessary 6.5:1 aspect ratio. A novel method of achieving such passivation based on an intermittent etching process is described.