Article
Crystallography
Alan G. G. Jacobs, Boris N. N. Feigelson, Joseph A. A. Spencer, Marko J. J. Tadjer, Jennifer K. K. Hite, Karl D. D. Hobart, Travis J. J. Anderson
Summary: Selective area doping is crucial for modern devices. In this study, efficient silicon ion activation in GaN was achieved through symmetrical multicycle rapid thermal annealing. The activation efficiency and mobility improved with increasing annealing temperature. The results demonstrate efficient dopant activation with low unintentional doping, making it suitable for high-voltage, high-power devices. Additionally, high activation and mobility have been achieved with GaN on sapphire, which offers commercial potential due to its large-area and robust substrates.
Article
Physics, Applied
Jun Uzuhashi, Jun Chen, Ashutosh Kumar, Wei Yi, Tadakatsu Ohkubo, Ryo Tanaka, Shinya Takashima, Masaharu Edo, Kacper Sierakowski, Michal Bockowski, Hideki Sakurai, Tetsu Kachi, Takashi Sekiguchi, Kazuhiro Hono
Summary: An investigation on annealing under different conditions after magnesium (Mg) implantation into GaN crystals revealed that ultra-high-pressure annealing (UHPA) effectively suppresses the formation of Mg-enriched defects, leading to improved p-type activation efficiency.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Ming Li, Mingchao Yang, Zhang Wen, Yi Yang, Weihua Liu, Chuanyu Han, Li Geng, Yue Hao
Summary: The activation of an Mg acceptor in p-GaN was investigated using rapid thermal annealing (RTA) assisted low-temperature supercritical fluid (SCF) treatment (RTA-A-SCF). The PL spectra showed a significant suppression of the luminescence band of the N vacancy after RTA-A-SCF treatment. Secondary ion mass spectrometer measurements indicated a noticeable decrease in H concentration, suggesting a decrease in Mg-H complexes in the p-GaN. In addition, ohmic contacts improved and the hole concentration increased by an order of magnitude. The activation mechanism of RTA-A-SCF treatment was further analyzed using X-ray photoelectron spectroscopy.
APPLIED PHYSICS EXPRESS
(2023)
Article
Engineering, Electrical & Electronic
Zheming Wang, Liguo Zhang, Rongkun Ji, Xiang Kan, Xuan Zhang, Yong Cai, Baoshun Zhang
Summary: Experimental results showed that increasing the implantation temperature had minor influence on the electrical activation of Si impurities in GaN, but led to a decrease in lattice strain. The average electron concentration and mobility remained relatively stable within a certain temperature range.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Physics, Applied
Takuya Nakashima, Emi Kano, Keita Kataoka, Shigeo Arai, Hideki Sakurai, Tetsuo Narita, Kacper Sierakowski, Michal Bockowski, Masahiro Nagao, Jun Suda, Tetsu Kachi, Nobuyuki Ikarashi
Summary: Investigation into defect time-evolution in Mg ion-implanted GaN revealed that annealing at 1573 K for an unprecedentedly long duration resulted in a significant reduction in defects inhibiting Mg activation. Additionally, the cathodoluminescence intensity of donor-acceptor pair originating from Mg acceptors increased with duration, indicating the potential to lower annealing temperature by prolonging duration. These findings suggest practical annealing technology for Mg ion-implanted GaN.
APPLIED PHYSICS EXPRESS
(2021)
Article
Physics, Applied
M. A. Reshchikov, O. Andrieiev, M. Vorobiov, D. Ye, D. O. Demchenko, K. Sierakowski, M. Bockowski, B. McEwen, V. Meyers, F. Shahedipour-Sandvik
Summary: Investigation of Be-implanted GaN samples subjected to annealing under different conditions revealed the activation of shallow Be-Ga acceptor and the presence of Be-Ga-related defects, as analyzed by low-temperature photoluminescence spectra.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
P. Jaroszynski, K. Sierakowski, R. Jakiela, M. Turek, M. Fijalkowski, T. Sochacki, M. Bockowski
Summary: Manganese diffusion in ion implanted gallium nitride crystals was studied. The manganese ions were implanted into a GaN layer grown on an ammonothermal gallium nitride substrate. After implantation, ultra-high pressure annealing was used to both remove the post-implantation damage and induce the diffusion of manganese ions. Two diffusion mechanisms were observed and the diffusion parameters for each mechanism, including activation energy and temperature-independent diffusion coefficients, were determined. The structural quality of the samples was also evaluated using X-ray diffractometry.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Guangyang Lin, Kun Qian, Hongjie Cai, Haochen Zhao, Jianfang Xu, Songyan Chen, Cheng Li, Ryan Hickey, James Kolodzey, Yuping Zeng
Summary: This study investigates the structural evolution and photoluminescence (PL) properties of low-temperature molecular beam epitaxy (MBE) grown Ge0.9338Sn0.0662 on Ge (001) substrate, after rapid thermal annealing (RTA). The results show gradual strain relaxation and Sn segregation with increasing RTA temperature. The PL intensity is enhanced in the annealed samples due to improved crystal quality and strain relaxation. The sample annealed at 500 degrees C exhibits the highest PL intensity, attributed to the formation of a Sn-component-graded (SCG) heterojunction.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Physics, Applied
M. Hayden Breckenridge, James Tweedie, Pramod Reddy, Yan Guan, Pegah Bagheri, Dennis Szymanski, Seiji Mita, Kacper Sierakowski, Michal Bockowski, Ramon Collazo, Zlatko Sitar
Summary: This study demonstrates high p-type conductivity and hole concentrations in Mg-implanted GaN under different diffusion budgets, with Mg activation and loss affecting hole conductivity. The challenge lies in controlling compensating defects to achieve desired hole conductivity and low Mg diffusion.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Applied
Maciej Matys, Takashi Ishida, Kyung Pil Nam, Hideki Sakurai, Tetsuo Narita, Tsutomu Uesugi, Michal Bockowski, Jun Suda, Tetsu Kachi
Summary: The proposed method demonstrates an edge termination technique for GaN-based one-sided abrupt p-n junctions, utilizing a combination of shallow negative bevel mesa and selective-area p-type doping. Through TCAD simulation and experimental verification, the approach significantly reduces the maximum electric field at the junction edge and enhances the breakdown voltage of the p-n diode.
APPLIED PHYSICS LETTERS
(2021)
Article
Environmental Sciences
J. S. Kim, N. Kumar, U. Jung, J. Park, Mu. Naushad
Summary: A mixed phase ZnSn(OH)6/ZnSnO3 photocatalyst was synthesized by calcining ZHS nanostructures via rapid thermal annealing process. The composition ratio of ZnSn(OH)6/ZnSnO3 was controlled by changing the duration of the RTA process. The obtained mixed-phase photocatalyst displayed the best photocatalytic performance under UVC light illumination, with nearly complete removal (>99%) of MO dye in 150 min.
Article
Materials Science, Coatings & Films
Dun-Bao Ruan, Kuei-Shu Chang-Liao, Shih-Han Yi, Fu-Yang Chu, Ji-Syuan Li, Chia-Wei Hsu, Jiayi Huang, Tzung-Yu Wu
Summary: It was found that efficient annealing effects on the gate stack can be achieved by using microwave annealing, leading to high performance characteristics in Ge pMOSFET devices.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Physics, Applied
A. Nardo, C. de Santi, C. Carraro, F. Sgarbossa, M. Buffolo, P. Diehle, S. Gierth, F. Altmann, H. Hahn, D. Fahle, M. Heuken, M. Fouchier, A. Gasparotto, E. Napolitani, G. Meneghesso, E. Zanoni, M. Meneghini
Summary: This study investigates the effectiveness of laser-induced treatment compared to rapid-thermal annealing for activating p-type dopants in Mg-doped GaN layers. The results show that laser treatment is an effective process for activation, even at low energy densities. The resistivity of the samples varies with temperature, and the analysis indicates that laser treatment has minimal effects on the concentration profile and surface roughness, except at higher energy densities where surface degradation is observed.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Zhaozhu Qu, Baolin Zhang, Guihua Yao, Changfang Li, Yuntao Peng, Qixin Li, Zhaohui Zeng, Yung-Kang Shen, Jianghui Dong
Summary: In this work, a novel set of methods is proposed for tuning the oxygen vacancy distribution through the combination of several effects. The results show that the incorporation of a Ti nano-island, the insertion of a thin layer of HfO2, and the annealing process under air conditions can significantly improve the performance of the resistive switching memory devices.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Huan Zhu, Ting Pan, Ryo Sato, Lusato Majula, Kwati Leonard, Hiroshige Matsumoto, Yoshimine Kato
Summary: TiO2/p-Si paste heterojunction structure with photovoltaic characteristics was successfully fabricated via rapid thermal annealing (RTA). The optimal RTA condition of 1200 degrees C for 2 seconds was identified, resulting in the lowest oxidation of Si paste and the best crystallization conditions, as well as the transformation of the Ti layer into the rutile TiO2 phase. The study demonstrated the potential application of Si paste films for future solar cell devices.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Benedikt Hauer, Claire E. Marvinney, Martin Lewin, Nadeemullah A. Mahadik, Jennifer K. Hite, Nabil Bassim, Alexander J. Giles, Robert E. Stahlbush, Joshua D. Caldwell, Thomas Taubner
ADVANCED FUNCTIONAL MATERIALS
(2020)
Article
Physics, Applied
Marko J. Tadjer, Fikadu Alema, Andrei Osinsky, Michael A. Mastro, Neeraj Nepal, Jeffrey M. Woodward, Rachael L. Myers-Ward, Evan R. Glaser, Jaime A. Freitas, Alan G. Jacobs, James C. Gallagher, Alyssa L. Mock, Daniel J. Pennachio, Jenifer Hajzus, Mona Ebrish, Travis J. Anderson, Karl D. Hobart, Jennifer K. Hite, Charles R. Eddy Jr.
Summary: Gallium oxide as an ultra-wide bandgap semiconductor shows significant potential in advancing power electronic devices due to its high breakdown electric field and mature substrate technology. However, a key challenge remains in growing electronic-grade epitaxial layers at rates consistent with the thickness needed for high voltage technologies. This study reports on the characterization of epitaxial layers grown at relatively high rates, showing improved quality and potential for future high voltage power device technologies.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Physics, Applied
Minh Anh Phan Nguyen, Jennifer Hite, Michael A. Mastro, Mehran Kianinia, Milos Toth, Igor Aharonovich
Summary: This study investigates the nature of quantum emitters in GaN grown on samples with different growth orientations, revealing consistent formation of quantum emitters in Ga-polar regions. Findings shed light on the origins of these quantum emitters and demonstrate site-selective formation in GaN. Through various tests, the overall defectivity of Ga-polar GaN synthesized using a specific growth procedure is attributed to the formation of quantum emitters.
APPLIED PHYSICS LETTERS
(2021)
Article
Materials Science, Coatings & Films
Michael A. Mastro, Charles R. Eddy, Marko J. Tadjer, Jennifer K. Hite, Jihyun Kim, Stephen J. Pearton
Summary: Recent advancements in bulk crystal growth of beta-Ga2O3 have led to commercialization of large-area substrates and high-quality films on (010) substrates, revealing subnanometer-scale facets and larger ridges on the surface. Recommendations for standardizing substrates to control ridge formation have been proposed based on density function theory calculations.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2021)
Article
Engineering, Electrical & Electronic
James C. Gallagher, Travis J. Anderson, Andrew D. Koehler, Mona A. Ebrish, Geoffrey M. Foster, Michael A. Mastro, Jennifer K. Hite, Brendan P. Gunning, Robert J. Kaplar, Karl D. Hobart, Francis J. Kub
Summary: This work focuses on fabricating vertical p-i-n GaN diodes using Raman spectroscopy to monitor carrier concentration, discovering that the uniformity of the wafers affects device performance. Avoiding electron-donating defects in the wafers significantly improves rectification ratio and reduces reverse bias leakage current.
JOURNAL OF ELECTRONIC MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Mona A. Ebrish, Travis J. Anderson, Alan G. Jacobs, James C. Gallagher, Jennifer K. Hite, Michael A. Mastro, Boris N. Feigelson, Yekan Wang, Michael Liao, Mark Goorsky, Karl D. Hobart
Summary: This research examines the optimal conditions for Mg ion implantation and activation, finding that in situ epitaxial-grown AlN caps are more suitable for GaN activation annealing, and a high dose is needed at the surface to facilitate ohmic contact formation. This work provides valuable information for achieving an electrical activation of implanted Mg while maintaining the integrity of the crystalline structure of GaN.
JOURNAL OF ELECTRONIC MATERIALS
(2021)
Article
Materials Science, Coatings & Films
Clarence Y. Chan, Shunya Namiki, Jennifer K. Hite, Michael A. Mastro, Syed B. Qadri, Xiuling Li
Summary: Metal-assisted chemical etching is a plasma-free method that can produce high aspect ratio structures, with potential applications in electronic and optoelectronic devices. The method was successfully demonstrated with ordered micropillar arrays of homoepitaxial GaN, showing promising results in spatially resolved photoluminescence. This approach may also be extended to InGaN and AlGaN, offering a facile and scalable processing route for III-nitride based devices.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2021)
Article
Instruments & Instrumentation
Md Shafkat Bin Hoque, Yee Rui Koh, Kiumars Aryana, Eric R. Hoglund, Jeffrey L. Braun, David H. Olson, John T. Gaskins, Habib Ahmad, Mirza Mohammad Mahbube Elahi, Jennifer K. Hite, Zayd C. Leseman, W. Alan Doolittle, Patrick E. Hopkins
Summary: This study investigates the thermal conductivity of buried substrates using the optical pump-probe technique SSTR, providing guidance for future measurements. The steady-state nature of SSTR allows it to measure the thermal properties of buried substrates that are traditionally challenging to measure with transient pump-probe techniques.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2021)
Article
Materials Science, Multidisciplinary
Yee Rui Koh, Md Shafkat Bin Hoque, Habib Ahmad, David H. Olson, Zeyu Liu, Jingjing Shi, Yekan Wang, Kenny Huynh, Eric R. Hoglund, Kiumars Aryana, James M. Howe, Mark S. Goorsky, Samuel Graham, Tengfei Luo, Jennifer K. Hite, W. Alan Doolittle, Patrick E. Hopkins
Summary: This study explores the thermal conductivity of homoepitaxial GaN films grown using different techniques, revealing that doped films exhibit significantly lower thermal conductivities. Defects and GaN/GaN interfaces limit thermal transport in unintentionally doped homoepitaxial GaN films.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Materials Science, Coatings & Films
Jeffrey M. Woodward, Samantha G. Rosenberg, David R. Boris, Michael J. Johnson, Scott G. Walton, Scooter D. Johnson, Zachary R. Robinson, Neeraj Nepal, Karl F. Ludwig Jr, Jennifer K. Hite, Charles R. Eddy Jr
Summary: Plasma-enhanced atomic layer deposition (PEALD) enables the epitaxial growth of ultrathin indium nitride (InN) films with reduced process temperatures and better control of layer thickness. The relationship between plasma properties and growth kinetics is crucial for optimizing growth parameters. In this study, in situ investigation using grazing incidence small-angle x-ray scattering (GISAXS) reveals that the production of nitrogen species in the plasma influences the growth mode, with high concentrations promoting island growth and low concentrations promoting layer-plus-island growth. The results demonstrate the potential to control the growth kinetics of epitaxial films during PEALD by manipulating specific plasma species generation regimes.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2022)
Article
Materials Science, Multidisciplinary
Alan G. Jacobs, Joseph A. Spencer, Jennifer K. Hite, Karl D. Hobart, Travis J. Anderson, Boris N. Feigelson
Summary: Codoping of gallium nitride with magnesium and silicon or oxygen via ion implantation and symmetric multicycle rapid thermal annealing is demonstrated. The results show enhanced photoluminescence, especially with oxygen codoping. The addition of nitrogen helps to balance stoichiometry and suppress defect photoluminescence signals. These findings have important implications for device design and the future use of ion implantation.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Review
Crystallography
Jennifer K. Hite
Summary: This paper reviews the basic issues in homoepitaxial growth of III-nitrides for vertical device technology. It focuses on using MOCVD to grow GaN and explores the effects of native substrate characteristics on material quality and device performance. The review also includes theoretical understanding of dopants in AlN and BN for future expansion into these materials.
Article
Crystallography
Alan G. G. Jacobs, Boris N. N. Feigelson, Joseph A. A. Spencer, Marko J. J. Tadjer, Jennifer K. K. Hite, Karl D. D. Hobart, Travis J. J. Anderson
Summary: Selective area doping is crucial for modern devices. In this study, efficient silicon ion activation in GaN was achieved through symmetrical multicycle rapid thermal annealing. The activation efficiency and mobility improved with increasing annealing temperature. The results demonstrate efficient dopant activation with low unintentional doping, making it suitable for high-voltage, high-power devices. Additionally, high activation and mobility have been achieved with GaN on sapphire, which offers commercial potential due to its large-area and robust substrates.
Article
Microscopy
Andrew J. Winchester, Travis J. Anderson, Jennifer K. Hite, Randolph E. Elmquist, Sujitra Pookpanratana
Summary: Photoemission electron microscopy (PEEM) is a powerful tool for studying electronic properties. Traditionally, it was mainly used with synchrotron light sources, but recent advancements in solid-state lasers have allowed for the development of laboratory-based PEEMs using laser-based UV light. This study reports on the characteristics of a laser-based UV light source integrated with a PEEM instrument and highlights the improved image quality compared to conventional light sources.
Proceedings Paper
Engineering, Electrical & Electronic
Clarence Y. Chan, Shunya Namiki, Jennifer K. Hite, Xiuling Li
Summary: In this study, photo-enhanced metal-assisted chemical etching was demonstrated on homoepitaxial n-UaN on HVPE GaN substrates. The etch rate achieved was comparable to or better than using RIE, with no degradation in band-edge emission observed.
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)
(2021)
