Physical Properties of AlGaN/GaN Heterostructures Grown on Vicinal Substrates

We report on the growth of Al0.25Ga0.75N/GaN heterostructures grown on low dislocation density vicinal surfaces of semi-insulating c-axis GaN substrates. Atomic force microscopy (AFM), photoluminescence (PL), cathodoluminescence (CL), high-resolution x-ray diffraction (HRXRD), secondary-ion mass spectroscopy (SIMS), Hall effect, and Raman spectroscopy have been used to assess structural and electrical properties as a function of substrate offcut. Bulk GaN substrates with vicinal offcut between 0.5° and 1.4° are optimal with respect to surface roughness and dopant incorporation. AFM, PL, and CL show decreasing Mg incorporation with increasing offcut angle. Raman spectroscopy, used to analyze biaxial strain, confirms essentially strain-free heterostructure growth on vicinal substrates with offcut angles between 0.5° and 1.4° off [0001] toward $$ [1\overline{1} 00] $$. Aluminum (Al) incorporation in the AlxGa1−xN barrier assessed by Raman vibration is in excellent agreement with trends found by HRXRD.

[1]  Shuji Nakamura,et al.  The Blue Laser Diode: GaN based Light Emitters and Lasers , 1997 .

[2]  Oliver Ambacher,et al.  Defect structure of epitaxial GaN films determined by transmission electron microscopy and triple-axis X-ray diffractometry , 1998 .

[3]  R. Dupuis,et al.  III-nitride heterostructure field-effect transistors grown on semi-insulating GaN substrate without regrowth interface charge , 2008 .

[4]  H. Amano,et al.  MOVPE growth of GaN on a misoriented sapphire substrate , 1991 .

[5]  C. D. Lee,et al.  Structural Properties of GaN Films Grown by Molecular Beam Epitaxy on Singular and Vicinal 6H-SiC(0001) , 2001 .

[6]  D. W. Pashley,et al.  The growth and structure of gold and silver deposits formed by evaporation inside an electron microscope , 1964 .

[7]  C. Thomsen,et al.  Local vibrational modes in Mg-doped GaN grown by molecular beam epitaxy , 1999 .

[8]  Tanya Paskova,et al.  Nitrides with Nonpolar Surfaces , 2008 .

[9]  Tetsu Kachi,et al.  Raman scattering from LO phonon‐plasmon coupled modes in gallium nitride , 1994 .

[10]  H. Amano,et al.  Compensation mechanism in MOCVD and MBE grown GaN : Mg , 2001 .

[11]  C. Meny,et al.  Interplay of electrons and phonons in heavily doped GaN epilayers , 1997 .

[12]  G. Snider,et al.  A self‐consistent solution of Schrödinger–Poisson equations using a nonuniform mesh , 1990 .

[13]  C. T. Foxon,et al.  MBE growth and characterization of magnesium-doped gallium nitride , 1998 .

[14]  Gregory L. Snider,et al.  Electron states in mesa‐etched one‐dimensional quantum well wires , 1990 .

[15]  S. Estreicher,et al.  Local vibrational modes of hydrogen in GaN: Observation and theory , 2006 .

[16]  M. Shimizu,et al.  Characterizations of GaN films and GaN/AlN super-lattice structures grown on vicinal sapphire (0 0 0 1) substrates by RF-MBE , 2005 .

[17]  Hadis Morkoç,et al.  Nitride Semiconductors and Devices , 1999 .

[18]  Bernard Gil,et al.  Raman determination of phonon deformation potentials in α-GaN , 1996 .

[19]  A. N. Smirnov,et al.  Raman and photoluminescence studies of biaxial strain in GaN epitaxial layers grown on 6H–SiC , 1997 .

[20]  T. Yuasa,et al.  Effect of Slight Misorientation of Sapphire Substrate on Metalorganic Chemical Vapor Deposition Growth of GaN , 1999 .

[21]  P. Chaudhari,et al.  Grain Growth and Stress Relief in Thin Films , 1972 .

[22]  A. Nakajima,et al.  Growth of Low-Dislocation-Density AlN under Ga Irradiation , 2006 .

[23]  T. Boufaden,et al.  Magnesium diffusion profile in GaN grown by MOVPE , 2008 .

[24]  M. Castellano,et al.  A probe for the investigation of the superconducting metastable state in YBa2Cu3O7−x step-edge junctions , 1998 .

[25]  H. Harima,et al.  Local Vibrational Modes in p‐Type GaN Observed by Raman Scattering , 1999 .

[26]  A. A. Allerman,et al.  Effect of threading dislocations on the Bragg peakwidths of GaN, AlGaN, and AlN heterolayers , 2005 .

[27]  R. Dupuis,et al.  Optimization of Fe doping at the regrowth interface of GaN for applications to III-nitride-based heterostructure field-effect transistors , 2007 .

[28]  J. Northrup Magnesium incorporation at (0001) inversion domain boundaries in GaN , 2003 .

[29]  D. Greve,et al.  Inversion of wurtzite GaN(0001) by exposure to magnesium , 1999 .

[30]  T. Chow,et al.  SiC Power Devices , 1996 .

[31]  Eric A. Armour,et al.  Advanced characterization studies of sapphire substrate misorientation effects on GaN‐based LED device development , 2003 .

[32]  C. Reynolds,et al.  Unintentional zinc diffusion in inp pn-homojunctions , 1995 .

[33]  Lian Li,et al.  Suppression of Spiral Growth in Molecular Beam Epitaxy of GaN on Vicinal 6H‐SiC(0001) , 2001 .

[34]  S. Tong,et al.  Step bunching of vicinal GaN(0001) surfaces during molecular beam epitaxy , 2000 .

[35]  J. Groenen,et al.  Coupling of GaN- and AlN-like longitudinal optic phonons in Ga1−xAlxN solid solutions , 1998 .

[36]  John F. Muth,et al.  Thermal conductivity, dislocation density and GaN device design , 2006 .

[37]  Hiroshi Harima,et al.  TOPICAL REVIEW: Properties of GaN and related compounds studied by means of Raman scattering , 2002 .

[38]  Time- and temperature-resolved photoluminescence of GaN:Mg epitaxial layers grown by MOVPE , 2001 .

[39]  T. Kozawa,et al.  THERMAL STRESS IN GAN EPITAXIAL LAYERS GROWN ON SAPPHIRE SUBSTRATES , 1995 .

[40]  R. Vaudo,et al.  MOVPE homoepitaxial growth on vicinal GaN(0001) substrates , 2005 .

[41]  Matthew Wormington,et al.  High resolution X-ray diffraction using a high brilliance source, with rapid data analysis by auto-fitting , 2001 .

[42]  T. Kimoto,et al.  Molecular‐beam epitaxy of AlN on off‐oriented SiC and demonstration of MISFET using AlN/SiC interface , 2005 .

[43]  C. Walle,et al.  First-principles calculations for defects and impurities: Applications to III-nitrides , 2004 .

[44]  W. Bonner,et al.  Orientation dependence of S, Zn, Si, Te, and Sn doping in OMCVD growth of InP and GaAs: application to DH lasers and lateral p—n junction arrays grown on non-planar substrates , 1991 .

[45]  Mark J. W. Rodwell,et al.  GaN HBT: toward an RF device , 2001 .

[46]  A. Gossard,et al.  Dislocation scattering in a two-dimensional electron gas , 2000, cond-mat/0003199.

[47]  T. Metzger,et al.  Raman study of the optical phonons in AlxGa1−xN alloys , 1997 .

[48]  K. Köhler,et al.  Hole conductivity and compensation in epitaxial GaN:Mg layers , 2000 .

[49]  John F. Muth,et al.  Accurate dependence of gallium nitride thermal conductivity on dislocation density , 2006 .

[50]  Daniel S. Green,et al.  Memory Effect and Redistribution of Mg into Sequentially Regrown GaN Layer by Metalorganic Chemical Vapor Deposition , 2003 .

[51]  Lianxi Zheng,et al.  Anisotropic Step-Flow Growth and Island Growth of GaN(0001) by Molecular Beam Epitaxy , 1999 .

[52]  Günther Tränkle,et al.  Reliability considerations of III-nitride microelectronic devices , 1999 .

[53]  Hajime Okumura,et al.  Impact of Vicinal Sapphire (0001) Substrates on the High-Quality AlN Films by Plasma-Assisted Molecular Beam Epitaxy , 2003 .

[54]  D. Clarke,et al.  MOSAIC STRUCTURE IN EPITAXIAL THIN FILMS HAVING LARGE LATTICE MISMATCH , 1997 .

[55]  W. Knap,et al.  Investigation of longitudinal‐optical phonon‐plasmon coupled modes in highly conducting bulk GaN , 1995 .

[56]  J. A. Grenko,et al.  Crystallographic plane dependent Fe and Si dopant incorporation and activation in InP , 2009 .

[57]  A. N. Smirnov,et al.  Composition dependence of optical phonon energies and Raman line broadening in hexagonal Al x Ga 1 − x N alloys , 2002 .

[58]  Krüger,et al.  Strain-related phenomena in GaN thin films. , 1996, Physical review. B, Condensed matter.

[59]  S. Denbaars,et al.  The growth of N-face GaN by MOCVD: effect of Mg, Si, and In , 2004 .

[60]  D. Jena,et al.  Effect of scattering by strain fields surrounding edge dislocations on electron transport in two-dimensional electron gases , 2002 .

[61]  M. Shur,et al.  Properties of advanced semiconductor materials : GaN, AlN, InN, BN, SiC, SiGe , 2001 .

[62]  R. Dupuis,et al.  Surface treatment on the growth surface of semi-insulating GaN bulk substrate for III-nitride heterostructure field-effect transistors , 2008 .

[63]  A. Nakajima,et al.  Growth of high-quality AlN with low pit density on SiC substrates , 2004 .

[64]  M. Neurock,et al.  Reactions of Laser-Ablated Iron Atoms with Nitrogen Atoms and Molecules. Matrix Infrared Spectra and Density Functional Calculations of Novel Iron Nitride Molecules , 1996 .

[65]  S. Einfeldt,et al.  Microstructure of heteroepitaxial GaN revealed by x-ray diffraction , 2003 .