02195nas a2200277 4500008004100000022001400041245010300055210006900158260001200227300001200239490000700251520133500258653002301593653000801616653003301624653002401657100001301681700001901694700002001713700002001733700001801753700002301771700002301794700002101817856007901838 1995 eng d a0361-523500aThe Influence of Nitrogen Ion Energy on the Quality of GaN Films Grown with Molecular Beam Epitaxy0 aInfluence of Nitrogen Ion Energy on the Quality of GaN Films Gro c04/1995 a249-2550 v243 a
Since the growth of GaN using molecular beam epitaxy (MBE) occurs under metastable growth conditions, activated nitrogen is required to drive the forward synthesis reaction. In the process of exciting the nitrogen using a plasma or ion-beam source, species with large kinetic energies are generated. Impingement on the growth surface by these species can result in subsurface damage to the growing film, as well as an enhancement of the reverse decomposition reaction rate. In this study, we investigate the effect of the kinetic energy of the impinging nitrogen ions during growth on the resulting optical and structural properties of GaN films. Strong band-edge photoluminescence and cathodoluminescence are found when a kinetic energy of ~10 eV are used, while luminescence is not detectable when the kinetic energies exceeds 18 eV. Also, we find that the use of conductive SiC substrates results in more homogeneous luminescence than the use of insulating sapphire substrates. This is attributed to sample surface charging in the case of sapphire substrates and subsequent variation in the incident ion flux and kinetic energy across the growth surface.This study clearly shows that the quality of GaN films grown by MBE are presently limited by damage from the impingement of high energy species on the growth surface.
10aActivated nitrogen10aGaN10amolecular beam epitaxy (MBE)10anitrogen ion energy1 aFu, T.C.1 aNewman, Nathan1 aJones, Erin, C.1 aChan, James, S.1 aLiu, Xiaohong1 aRubin, Michael, D.1 aCheung, Nathan, W.1 aWeber, Eicke, R. uhttps://facades.lbl.gov/publications/influence-nitrogen-ion-energy-quality01809nas a2200361 4500008004100000022001400041245007600055210006900131260001200200300001400212490000700226520074400233653001400977653001900991653001801010653002601028653002101054653002101075653002401096653001901120653002201139100002001161700002301181700002601204700002001230700002201250700001901272700001801291700002101309700001601330700002301346856007801369 1995 eng d a0003-695100aThermal Annealing Characteristics of Si and Mg-implanted GaN Thin Films0 aThermal Annealing Characteristics of Si and Mgimplanted GaN Thin c03/1996 a2702-27040 v683 aIn this letter, we report the results of ion implantation of GaN using 28Si and 23Mg species. Structural and electrical characterizations of the GaN thin films after thermal annealing show that native defects in the GaN films dominate over implant doping effects. The formation energies of the annealing induced defects are estimated to range from 1.4 to 3.6 eV. A 30 keV10^14 cm-2 Mg implant results in the decrease of the free-carrier concentration by three orders of magnitude compared to unimplanted GaN up to an annealing temperature of 690 °C. Furthermore, we have observed the correlation between these annealing-induced defects to both improved optical and electrical properties.
10aannealing10acrystal doping10adefect states10aelectrical properties10agallium nitrides10aion implantation10amagnesium additions10amicrostructure10asilicon additions1 aChan, James, S.1 aCheung, Nathan, W.1 aSchloss, Lawrence, F.1 aJones, Erin, C.1 aWong, William, S.1 aNewman, Nathan1 aLiu, Xiaohong1 aWeber, Eicke, R.1 aGassman, A.1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/thermal-annealing-characteristics-si01409nas a2200241 4500008004100000050001400041245008900055210006900144520063300213100001900846700001300865700001200878700002900890700002300919700002000942700002000962700002300982700002201005700001701027700002301044700002101067856007901088 1994 eng d aLBL-3729600aFundamental Materials-Issues Involved in the Growth of GaN by Molecular Beam Epitaxy0 aFundamental MaterialsIssues Involved in the Growth of GaN by Mol3 aGallium nitride is one of the most promising materials for ultraviolet and blue light-emitting diodes and lasers. Both Molecular Beam Epitaxy (MBE) and Metal-Organic Chemical Vapor Deposition (MOCVD) have recently made strong progress in fabricating high-quality epitaxial GaN thin films. In this paper, we review materials-related issues involved in MBE growth. We show that a strong understanding of the unique meta-stable growth process allows us to correctly predict the optimum conditions for epitaxial GaN growth. The resulting structural, electronic and optical properties of the GaN films are described in detail.
1 aNewman, Nathan1 aFu, T.C.1 aLiu, Z.1 aLiliental-Weber, Zuzanna1 aRubin, Michael, D.1 aChan, James, S.1 aJones, Erin, C.1 aRoss, Jennifer, T.1 aTidswell, Ian, M.1 aYu, Kin, Man1 aCheung, Nathan, W.1 aWeber, Eicke, R. uhttps://facades.lbl.gov/publications/fundamental-materials-issues-involved01308nas a2200193 4500008004100000024001100041245010400052210006900156260003100225490000800256520065800264100002000922700001300942700002300955700002300978700001901001700002301020856007101043 1993 eng d aUC-40000aComparison of AIN Films Grown by RF at Magnetron Sputtering and Ion-Assisted Molecular Beam Epitaxy0 aComparison of AIN Films Grown by RF at Magnetron Sputtering and aSan Francisco, CAc04/19930 v3003 aCrystalline aluminum nitride (AlN) thin films were formed on various substrates by using RF magnetron sputtering of an A1 target in a nitrogen plasma and also by ion-assisted molecular beam epitaxy (IAMBE). Basal-oriented AlN/(111) Si showed a degradation of crystallinity with increased substrate temperature from 550 to 770 °C, while the crystallinity of AlN/(0001) Al2O3 samples improved from 700 to 850 °C. The optical absorption characteristics of the AlN/(0001) Al2O3 films as grown by both deposition methods revealed a decrease in sub-band gap absorption with increased substrate temperature.
1 aChan, James, S.1 aFu, T.C.1 aCheung, Nathan, W.1 aRoss, Jennifer, T.1 aNewman, Nathan1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/comparison-ain-films-grown-rf