@misc{linthicum_gehrke_thomson_carlson_rajagopal_davis_2008, title={Pendeoepitaxial gallium nitride semiconductor layers on silicon carbide substrates}, volume={7,378,684}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Linthicum, K. J. and Gehrke, T. and Thomson, D. B. and Carlson, E. P. and Rajagopal, P. and Davis, R. F.}, year={2008} } @misc{cuomo_williams_hanser_carlson_thomas_2004, title={MIIIN based materials and methods and apparatus for producing same}, volume={6,784,085}, number={2004 Aug. 31}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Cuomo, J. J. and Williams, N. M. and Hanser, A. D. and Carlson, E. P. and Thomas, D. T.}, year={2004}, month={Aug} } @misc{linthicum_gehrke_thomson_carlson_rajagopal_davis_2002, title={Pendeoepitaxial gallium nitride semiconductor layers on silicon carbide substrates}, volume={6,462,355}, number={2002 Oct. 8}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Linthicum, K. J. and Gehrke, T. and Thomson, D. B. and Carlson, E. P. and Rajagopal, P. and Davis, R. F.}, year={2002} } @misc{linthicum_gehrke_thomson_carlson_rajagopal_davis_2002, title={Pendeoepitaxial methods of fabricating gallium nitride semiconductor layers on silicon carbide substrates by lateral growth from sidewalls of masked posts, ang gallium nitratde semiconductor structures fabricated thereby}, volume={6,376,339}, number={2002 Apr. 23}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Linthicum, K. J. and Gehrke, T. and Thomson, D. B. and Carlson, E. P. and Rajagopal, P. and Davis, R. F.}, year={2002} } @article{park_maria_cuomo_chang_muth_kolbas_nemanich_carlson_bumgarner_2002, title={X-ray and Raman analyses of GaN produced by ultrahigh-rate magnetron sputter epitaxy}, volume={81}, ISSN={["0003-6951"]}, DOI={10.1063/1.1506781}, abstractNote={Thick films of GaN were studied by x-ray diffraction and Raman spectroscopy. The GaN thick films were deposited on (0001) sapphire using ultrahigh-rate magnetron sputter epitaxy with typical growth rates as high as 10–60 μm/min. The width of the x-ray rocking curve from the (0002) reflection for the sample produced by this technique is ∼300 arcsec, which is unprecedented for GaN produced by a sputtering-type process. Our recent sample shows an x-ray rocking curve width of 240 arcsec. Only allowed modes were observed in the polarized Raman spectra. The background free carrier concentration is lower than 3×1016 cm−3. The phonon lifetime of the Raman E2(2) mode of the sputtered GaN was comparable to that of bulk single crystal GaN grown by sublimation. The quality of the film was uniform across the wafer. The film was thermally stable upon annealing in N2 ambient. The x-ray and Raman analyses revealed that the sputtered GaN films are of high crystalline quality.}, number={10}, journal={APPLIED PHYSICS LETTERS}, author={Park, M and Maria, JP and Cuomo, JJ and Chang, YC and Muth, JF and Kolbas, RM and Nemanich, RJ and Carlson, E and Bumgarner, J}, year={2002}, month={Sep}, pages={1797–1799} } @misc{ronning_carlson_davis_2001, title={Ion implantation into gallium nitride}, volume={351}, ISSN={["1873-6270"]}, DOI={10.1016/S0370-1573(00)00142-3}, abstractNote={This comprehensive review is concerned with studies regarding ion implanted gallium nitride (GaN) and focuses on the improvements made in recent years. It is divided into three sections: (i) structural properties, (ii) optical properties and (iii) electrical properties. The first section includes X-ray diffraction (XRD), transmission electron microscopy (TEM), secondary ion mass spectroscopy (SIMS), Rutherford Backscattering (RBS), emission channeling (EC) and perturbed γγ-angular correlation (PAC) measurements on GaN implanted with different ions and doses at different temperatures as a function of annealing temperature. The structural changes upon implantation and the respective recovery upon annealing will be discussed. Several standard and new annealing procedures will be presented and discussed. The second section describes mainly photoluminescence (PL) studies, however, the results will be discussed with respect to Raman and ellipsometry studies performed by other groups. We will show that the PL-signal is very sensitive to the processes occurring during implantation and annealing. The results of Hall and C–V measurements on implanted GaN are presented in Section 3. We show and discuss the difficulties in achieving electrical activation. However, optical and electrical properties are both a result of the structural changes upon implantation and annealing. Each section will be critically discussed with respect to the existing literature, and the main conclusions are drawn from the interplay of the results obtained from the different techniques used/reviewed.}, number={5}, journal={PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS}, author={Ronning, C and Carlson, EP and Davis, RF}, year={2001}, month={Sep}, pages={349–385} } @misc{linthicum_gehrke_thomson_carlson_rajagopal_davis_2001, title={Pendeoepitaxial gallium nitride semiconductor layers on silicon carbide substrates}, volume={6,177,688}, number={2001 Jan. 23}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Linthicum, K. J. and Gehrke, T. and Thomson, D. B. and Carlson, E. P. and Rajagopal, P. and Davis, R. F.}, year={2001} } @article{gehrke_linthicum_rajagopal_preble_carlson_robin_davis_2000, title={Pendeo-epitaxy (TM) process for aluminum gallium nitride thin films on silicon carbide substrates via metalorganic chemical vapor deposition}, volume={338}, number={3}, journal={Materials Science Forum}, author={Gehrke, T. and Linthicum, K. J. and Rajagopal, P. and Preble, E. A. and Carlson, E. P. and Robin, B. M. and Davis, R. F.}, year={2000}, pages={1491–1494} } @article{ronning_hofsass_stotzler_deicher_carlson_hartlieb_gehrke_rajagopal_davis_2000, title={Photoluminescence characterization of Mg implanted GaN}, volume={5}, number={2000}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Ronning, C. and Hofsass, H. and Stotzler, A. and Deicher, M. and Carlson, E. P. and Hartlieb, P. J. and Gehrke, T. and Rajagopal, P. and Davis, R. F.}, year={2000}, pages={U622–628} } @article{ronning_linthicum_carlson_hartlieb_thomson_gehrke_davis_1999, title={Characterization of Be-implanted GaN annealed at high temperatures}, volume={4S1}, number={G3.17}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Ronning, C. and Linthicum, K. J. and Carlson, E. P. and Hartlieb, P. J. and Thomson, D. B. and Gehrke, T. and Davis, R. F.}, year={1999} } @article{linthicum_gehrke_thomson_carlson_rajagopal_smith_batchelor_davis_1999, title={Pendeo-epitaxy of gallium nitride thin films}, volume={75}, DOI={10.1063/1.124317}, abstractNote={Pendeoepitaxy, a form of selective lateral growth of GaN thin films has been developed using GaN/AlN/6H–SiC(0001) substrates and produced by organometallic vapor phase epitaxy. Selective lateral growth is forced to initiate from the (112̄0) GaN sidewalls of etched GaN seed forms by incorporating a silicon nitride seed mask and employing the SiC substrate as a pseudomask. Coalescence over and between the seed forms was achieved. Transmission electron microscopy revealed that all vertically threading defects stemming from the GaN/AlN and AlN/SiC interfaces are contained within the seed forms and a substantial reduction in the dislocation density of the laterally grown GaN. Atomic force microscopy analysis of the (112̄0) face of discrete pendeoepitaxial structures revealed a root mean square roughness of 0.98 Å. The pendeoepitaxial layer photoluminescence band edge emission peak was observed to be 3.454 eV and is blueshifted by 12 meV as compared to the GaN seed layer.}, number={2}, journal={Applied Physics Letters}, author={Linthicum, K. J. and Gehrke, T. and Thomson, D. B. and Carlson, E. P. and Rajagopal, P. and Smith, T. and Batchelor, D. and Davis, R.}, year={1999}, pages={196–198} } @article{zheleva_smith_thomson_gehrke_linthicum_rajagopal_carlson_ashmawi_davis_1999, title={Pendeo-epitaxy: A new approach for lateral growth of gallium nitride structures}, volume={4S1}, number={G3.38}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Zheleva, T. S. and Smith, S. A. and Thomson, D. B. and Gehrke, T. and Linthicum, K. J. and Rajagopal, P. and Carlson, E. and Ashmawi, W. M. and Davis, R. F.}, year={1999} } @article{linthicum_gehrke_thomson_tracy_carlson_smith_zheleva_zorman_mehregany_davis_1999, title={Process routes for low defect-density GaN on various substrates employing pendeo-epitaxial growth techniques}, volume={4S1}, number={G4.9}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Linthicum, K. J. and Gehrke, T. and Thomson, D. B. and Tracy, K. M. and Carlson, E. P. and Smith, T. P. and Zheleva, T. S. and Zorman, C. A. and Mehregany, M. and Davis, R. F.}, year={1999} } @article{king_carlson_therrien_christman_nemanich_davis_1999, title={X-ray photoelectron spectroscopy analysis of GaN/(0001)AlN and AlN/(0001)GaN growth mechanisms}, volume={86}, ISSN={["0021-8979"]}, DOI={10.1063/1.371564}, abstractNote={The mechanisms of growth of GaN on AlN and AlN on GaN via gas source-molecular beam epitaxy with NH3 as the nitrogen source have been investigated using x-ray photoelectron spectroscopy, low energy electron diffraction, and Auger electron spectroscopy. The growth of GaN on AlN at low temperatures (650–750 °C) occurs via a Stranski–Krastanov 2D→3D type mechanism with the transition to 3D growth occurring at ≈10–15 Å. The mechanism changes to Frank van der Merwe (FM)/layer-by-layer growth above 800 °C. The growth of AlN on GaN occurred via a FM layer-by-layer mechanism within the 750–900 °C temperature range investigated. We propose a model based on the interaction of ammonia and atomic hydrogen with the GaN/AlN surfaces which indicates that the surface kinetics of hydrogen desorption and ammonia decomposition are the factors that determine the GaN growth mechanism.}, number={10}, journal={JOURNAL OF APPLIED PHYSICS}, author={King, SW and Carlson, EP and Therrien, RJ and Christman, JA and Nemanich, RJ and Davis, RF}, year={1999}, month={Nov}, pages={5584–5593} } @article{hanser_wolden_perry_zheleva_carlson_banks_therrien_davis_1998, title={Analysis of reactor geometry and diluent gas flow effects on the metalorganic vapor phase epitaxy of AlN and GaN thin films on alpha(6H)-SiC substrates}, volume={27}, ISSN={["0361-5235"]}, DOI={10.1007/s11664-998-0394-7}, number={4}, journal={JOURNAL OF ELECTRONIC MATERIALS}, author={Hanser, AD and Wolden, CA and Perry, WG and Zheleva, T and Carlson, EP and Banks, AD and Therrien, RJ and Davis, RF}, year={1998}, month={Apr}, pages={238–245} } @article{ronning_carlson_thomson_davis_1998, title={Optical activation of Be implanted into GaN}, volume={73}, ISSN={["0003-6951"]}, DOI={10.1063/1.122225}, abstractNote={Single crystalline (0001) gallium nitride layers were implanted with beryllium. Photoluminescence (PL) measurements were subsequently performed as a function of implantation dose and annealing temperature. One new line in the PL spectra at 3.35 eV provided strong evidence for the presence of optically active Be acceptors and has been assigned to band–acceptor (eA) recombinations. The determined ionization energy of 150±10 meV confirmed that isolated Be has the most shallow acceptor level in GaN. Co-implantation of nitrogen did not enhance the activation of the Be acceptors.}, number={12}, journal={APPLIED PHYSICS LETTERS}, author={Ronning, C and Carlson, EP and Thomson, DB and Davis, RF}, year={1998}, month={Sep}, pages={1622–1624} } @article{parikh_suvkhanov_lioubtchenko_carlson_bremser_bray_davis_hunn_1997, title={Ion implantation of epitaxial GaN films: Damage, doping and activation}, volume={127}, ISSN={["0168-583X"]}, DOI={10.1016/S0168-583X(97)00076-1}, abstractNote={Monocrystalline GaN films grown on AlN buffer layers previously deposited on 6HSiC(0001) wafers and having dislocation densities on the order of 107 cm/cm3 beyond 0.5 μm from the initial growth interface have been achieved via chemical vapor deposition (CVD). The absence of low angle grain boundaries invariably extant in GaN films deposited on sapphire substrates and the relatively low dislocation densities and absence of stacking faults and twinning in the implantation regions of the films make them the best materials available for the study of implantation doping. In our initial study, 160 keV Si (n-type) and 120 keV Mg (p-type) with projected range ∼ 110 nm and fluences of 1e14, 5e14 and 1e15 cm−2 were implanted at both room temperature and 550°C. The samples were characterized by Rutherford backscattering (RBS)/channeling and photoluminescence (PL) techniques before and after implantation. RBS/channeling results of virgin and as-implanted GaN for 120 keV Mg at 550°C and 1e15 cm−2 fluence showed that even at this comparatively high dose the implantation damage is very little. However the characteristic PL signal which was present before the implantation disappeared even for the lowest dose (1e14 cm−2). These samples were annealed in a rapid thermal annealing furnace at 1000°C, and damage recovery and dopant activation were measured by PL, RBS/channeling and Cross-Sectional TEM (XTEM).}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS}, author={Parikh, N and Suvkhanov, A and Lioubtchenko, M and Carlson, E and Bremser, M and Bray, D and Davis, R and Hunn, J}, year={1997}, month={May}, pages={463–466} } @misc{cuomo_williams_hanser_carlson_thomas, title={Method and apparatus for producing MIIIN columns and MIIIN materials grown thereon}, volume={6,692,568}, number={2004 Feb. 17}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Cuomo, J. J. and Williams, N. M. and Hanser, A. D. and Carlson, E. P. and Thomas, D. T.} }