scholarly journals High-temperature structural behavior of Ni/Au Contact on GaN(0001)

2001 ◽  
Vol 6 ◽  
Author(s):  
Chong Cook Kim ◽  
Jong Kyu Kim ◽  
Jong-Lam Lee ◽  
Jung Ho Je ◽  
Min-Su Yi ◽  
...  
Keyword(s):  
Structural Evolution ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
X Ray ◽  
X Ray Scattering ◽  
Smooth Interface ◽  
Resolution Electron ◽  
Device Reliability ◽  
Relationship Of

We investigated the structural evolution of the Ni/Au contact on GaN(000l) during annealing in N2, using in-situ x-ray diffraction, anomalous x-ray scattering, and high resolution electron microscopy. GaN decomposition occurred mostly along GaN dislocations at temperature higher than 500°C. The decomposed Ga diffused into Au and Ni substitutional positions, and the decomposed nitrogen reacted with Ni, forming Ni4N. Interestingly, Ni4N was grown epitaxially. The epitaxial relationship of the Ni4N, Au, and Ni was identified as M(111)//GaN(0002) and M[1 −1 0]//GaN[1 1 −2 0] (M= Ni4N, Au, and Ni). At dislocation free regions, however, the atomically smooth interface remained intact up to 700 °C. Remarkable improvement of device reliability is expected in the contact on dislocation free regions compared with the contact on dislocations.

Structural Evolution of Ni/Au Contact on GaN(0001)

2000 ◽  
Vol 639 ◽  
Author(s):  
Chong Cook Kim ◽  
Jong Kyu Kim ◽  
Jong-Lam Lee ◽  
Min-Su Yi ◽  
Jin-Woo Kim ◽  
...  
Keyword(s):  
Structural Evolution ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
X Ray ◽  
Thermally Activated ◽  
X Ray Scattering ◽  
Resolution Electron ◽  
Relationship Of

ABSTRACTWe investigated the structural behavior of the Ni/Au contact on GaN(000l) during annealing in N2, using in-situ x-ray diffraction, anomalous x-ray scattering, and high resolution electron microscopy. Thermally activated atomic mobility caused the two metal atoms, Au and Ni, to interdiffuse during annealing and form solid solutions. At temperature higher than 500°C, GaN decomposition and reactions occurred mostly along GaN dislocations. By decomposed nitrogen reacted with Ni, interestingly, epitaxial Ni4N phase was formed. The epitaxial relationship of the Ni4N, Au, and Ni was identified as M(111)//GaN(0002) and M[0 1 1]//GaN[0211] (M= Ni4N, Au, and Ni).

The process and mechanism of the GaN nanoparticles formed by nitridation of β-Ga2O3 crystal

2017 ◽  
Vol 31 (10) ◽  
pp. 1750108 ◽  
Author(s):  
Xiao-Jun Cui ◽  
Liang-Ling Wang
Keyword(s):  
Vapor Deposition ◽  
Surface Defect ◽  
Chemical Vapor ◽  
Hexagonal Structure ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
X Ray ◽  
Diffraction Peaks ◽  
Relationship Of ◽  
Gan Film

The process of conversion from [Formula: see text]-Ga2O3 single crystal to gallium nitride (GaN) in an atmosphere of NH3 by chemical vapor deposition is investigated. The surface morphology and microstructure of the GaN nanoparticles are observed by scanning electron microscope, which indicates that the growth of GaN is via the Volmer–Weber mechanism. The [Formula: see text]-Ga2O3 is firstly evaporated at high temperature to form the porous layer, followed by the surface-defect induced GaN nucleation formation. The crystalline structure and epitaxial relationship of the GaN nanoparticles are investigated by X-ray diffraction (XRD) via [Formula: see text]–[Formula: see text], showing GaN (0002) and (0004) diffraction peaks in the XRD spectra. It is concluded that the polycrystalline GaN film with hexagonal structure has a strong c-axis preferential orientation.

Atomic Level Investigations of W-Si Multilayers by High Resolution Tem and X Ray Scattering

1987 ◽  
Vol 103 ◽  
Author(s):  
S. R Nutt ◽  
J. E. Keem
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Interface Roughness ◽  
Bilayer Thickness ◽  
Individual Layer ◽  
X Ray ◽  
X Ray Scattering ◽  
Resolution Electron ◽  
Ray Scattering

ABSTRACTWe have prepared multilayer films of W-Si with bilayer repeat spacing from approximately 1.5 nm to 9 nm and performed high resolution electron microscopy and low angle x-ray scattering on them. Average composition estimates as inferred from deposition conditions, x ray scattering and electron microscopy are compared. Determinations of the individual layer thickness ratios by electron microscopy and x ray scattering vary significantly from expectations as the bilayer thickness approaches 1.5 nm. Layer intermixing to increase as the bilayer thickness decreases. Composition profiles as inferred from the Cuk x ray profile are compared to those inferred from the high resolution electron micrographs. Visual observations from melectron microscopy are presented indicating that the interface roughness is rapidly damped in the W-Si multilayer system. Estimates of the layer uniformity are made from the high resolution images.

Kinetic Study on the Formation of the Aragonite-Like Phase Ba(CuOx)1-Y(CO3)y

1995 ◽  
Vol 398 ◽  
Author(s):  
A. Tomasi ◽  
E. Galvanetto ◽  
F.C. Matacotta ◽  
P. Nozar ◽  
P. Scardi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Techniques ◽  
Formation Kinetics ◽  
Resolution Electron ◽  
Thermal Analysis Techniques ◽  
Kinetics Of

ABSTRACTA systematic study on phase formation and stabilisation in the Ba-Cu-C-O system in the temperature range 20-500°C, under various atmospheres, by traditional thermal analysis techniques, high temperature X-ray diffraction and high resolution electron microscopy, has permitted to identify and characterise the formation kinetics of a new copper containing phase isomorphic to γ-BaCO3.

A structural model for charoite

2009 ◽  
Vol 73 (5) ◽  
pp. 883-890 ◽  
Author(s):  
I. V. Rozhdestvenskaya ◽  
T. Kogure ◽  
E. Abe ◽  
V. A. Drits
Keyword(s):  
Structural Model ◽  
High Resolution Electron Microscopy ◽  
Tubular Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Resolution Electron ◽  
Xrd Patterns ◽  
Silicon Oxygen ◽  
Monoclinic Cell

AbstractThe crystal structure of charoite was investigated mainly by using selected-area electron diffraction (SAED), X-ray diffraction (XRD) and high-resolution electron microscopy (HREM). SAED and XRD patterns indicate that the structure has a monoclinic cell: a = 32.296, b = 19.651, c = 7.16 Å, β = 96.3° and V = 4517 Å3. The space group inferred from systematic absences and HREM images is P21/m. A model of the charoite structure is proposed that is based on the features of related Ca-alkaline silicate structures and HREM images. The structure of charoite consists of three different silicon-oxygen radicals (polymerized SiO4 tetrahedra) which are located between Ca polyhedra. Two of these radicals form continuous tubular structures comprising pectolite-like tetrahedral chains. Calcium polyhedra are joined to form blocks, each of which consists of four columns sharing edges and apices. Potassium and H2O molecules are probably located inside the tubular silicate radicals. From these results, a general formula is derived: K6-7(Ca,Na)18[(Si6O17)(Si12O30)(Si18O45)](OH,F)2.nH2O with two formula units in the unit cell (Z = 2).

Elastic and nanostructural properties of Cu/Pd superlattices

1992 ◽  
Vol 7 (6) ◽  
pp. 1356-1369 ◽  
Author(s):  
B.M. Davis ◽  
D.X. Li ◽  
D.N. Seidman ◽  
J.B. Ketterson ◽  
R. Bhadra ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Brillouin Scattering ◽  
High Resolution Electron Microscopy ◽  
Anomalous Behavior ◽  
Electron Beam Evaporation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composition Modulation ◽  
Tension Tests ◽  
Resolution Electron

A series of Cu/Pd superlattices with composition modulation wavelengths (Λ's) ranging from 1.6 to 3.5 nm and a strong [111] growth texture were prepared by electron beam evaporation. The elastic properties of the films were examined using the methods of uniaxial tension tests [a Young's modulus (1/s11), where sij is an elastic compliance] with the applied load parallel to the plane of the Cu/Pd interface and Brillouin scattering [a shear modulus (1/s44) with the shear waves parallel to the plane of the Cu/Pd interface]. Also, the films were characterized using both x-ray diffraction and high-resolution electron microscopy; this was done to assess the effect of the nanostructure on a possible “supermodulus effect.” The films are nanostructurally very similar to the superlattice films employed in previous studies at Northwestern in which a supermodulus effect was reported. But, contrary to previous studies, no anomalous behavior was observed for the measured elastic properties of the thin films. Therefore the present results negate the earlier results and cast a serious doubt on the existence of a supermodulus effect.

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