Polarity determination of a GaN thin film on sapphire (0001) with x-ray standing waves

1998 ◽  
Vol 84 (3) ◽  
pp. 1703-1705 ◽  
Author(s):  
A. Kazimirov ◽  
G. Scherb ◽  
J. Zegenhagen ◽  
T.-L. Lee ◽  
M. J. Bedzyk ◽  
...  
Keyword(s):  
Thin Film ◽  
Standing Waves ◽  
X Ray ◽  
Polarity Determination

Determination of Stoichiometry of GaAs Component in (Gaas)Ge Epitaxially Grown Thin Films by Electron Microprobe X-Ray Analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 264-265
Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
R. J. Baird
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Compound Semiconductors ◽  
Energy Dispersive Analysis ◽  
X Ray ◽  
Metastable Alloys ◽  
Lower Voltage

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.

Polarity Determination in Sphalerite and Wurtzite Structures

1990 ◽  
Vol 48 (2) ◽  
pp. 500-501
Author(s):  
Stuart McKernan ◽  
C. Barry Carter
Keyword(s):  
Opposite Polarity ◽  
Single Domain ◽  
Polar Material ◽  
Electron Microscopic ◽  
Dynamical Interaction ◽  
X Ray ◽  
Polarity Determination ◽  
The Absolute ◽  
Microscopic Techniques

The determination of the absolute polarity of a polar material is often crucial to the understanding of the defects which occur in such materials. Several methods exist by which this determination may be performed. In bulk, single-domain specimens, macroscopic techniques may be used, such as the different etching behavior, using the appropriate etchant, of surfaces with opposite polarity. X-ray measurements under conditions where Friedel’s law (which means that the intensity of reflections from planes of opposite polarity are indistinguishable) breaks down can also be used to determine the absolute polarity of bulk, single-domain specimens. On the microscopic scale, and particularly where antiphase boundaries (APBs), which separate regions of opposite polarity exist, electron microscopic techniques must be employed. Two techniques are commonly practised; the first [1], involves the dynamical interaction of hoLz lines which interfere constructively or destructively with the zero order reflection, depending on the crystal polarity. The crystal polarity can therefore be directly deduced from the relative intensity of these interactions.

Problems in Thin-Film X-ray Quantification

1990 ◽  
Vol 48 (2) ◽  
pp. 458-459
Author(s):  
J N Chapman ◽  
W A P Nicholson
Keyword(s):  
Thin Film ◽  
Specimen Thickness ◽  
X Rays ◽  
Characteristic Peak ◽  
Local Composition ◽  
X Ray ◽  
Measured Ratio ◽  
Path Lengths ◽  
Composition Changes

Energy dispersive x-ray microanalysis (EDX) is widely used for the quantitative determination of local composition in thin film specimens. Extraction of quantitative data is usually accomplished by relating the ratio of the number of atoms of two species A and B in the volume excited by the electron beam (nA/nB) to the corresponding ratio of detected characteristic photons (NA/NB) through the use of a k-factor. This leads to an expression of the form nA/nB = kAB NA/NB where kAB is a measure of the relative efficiency with which x-rays are generated and detected from the two species.Errors in thin film x-ray quantification can arise from uncertainties in both NA/NB and kAB. In addition to the inevitable statistical errors, particularly severe problems arise in accurately determining the former if (i) mass loss occurs during spectrum acquisition so that the composition changes as irradiation proceeds, (ii) the characteristic peak from one of the minority components of interest is overlapped by the much larger peak from a majority component, (iii) the measured ratio varies significantly with specimen thickness as a result of electron channeling, or (iv) varying absorption corrections are required due to photons generated at different points having to traverse different path lengths through specimens of irregular and unknown topography on their way to the detector.

scholarly journals Structural determination of the Si(111) √3×√3-Bi surface by x-ray standing waves and scanning tunneling microscopy

1994 ◽  
Vol 50 (16) ◽  
pp. 12246-12249 ◽  
Author(s):  
J. C. Woicik ◽  
G. E. Franklin ◽  
Chien Liu ◽  
R. E. Martinez ◽  
I.-S. Hwong ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Standing Waves ◽  
Scanning Tunneling ◽  
Structural Determination ◽  
Tunneling Microscopy ◽  
X Ray

Adsorption height determination of nonequivalent C and O species of PTCDA on Ag(110) using x-ray standing waves

2013 ◽  
Vol 87 (4) ◽  
Author(s):  
G. Mercurio ◽  
O. Bauer ◽  
M. Willenbockel ◽  
N. Fairley ◽  
W. Reckien ◽  
...  
Keyword(s):  
Standing Waves ◽  
X Ray ◽  
Height Determination

Determination of the Mechanical Response of Thin Films with X-Rays

1993 ◽  
Vol 308 ◽  
Author(s):  
I. C. Noyan ◽  
G. Sheikh
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Response ◽  
Strain Analysis ◽  
Local Strain ◽  
X Rays ◽  
Stress Strain ◽  
X Ray ◽  
The Individual

ABSTRACTThe mechanical response of a specimen incorporating thin films is dictated by a combination of fundamental mechanical parameters such as Young's moduli of the individual layers, and by configurational parameters such as adhesion strength at the interface(s), residual stress distribution and other process dependent factors. In most systems, the overall response will be dominated by the properties of the (much thicker) substrate. Failure within the individual layers, on the other hand, is dependent on the local strain distributions and can not be predicted from the substrate values alone. To better understand the mechanical response of these systems, the strain within the individual layers of the thin film system must be measured and correlated with applied stresses. Phase selectivity of X-ray stress/strain analysis techniques is well suited for this purpose. In this paper, we will review the use of the traditional x-ray stress/strain analysis methods for the determination of the mechanical properties of thin film systems.

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