Non-destructive X-ray Analysis Research Articles

Dynamical X-Ray Diffraction Analysis of Triple-Junction Solar Cells on Germanium (001) Substrates

We demonstrate the dynamical x-ray diffraction analysis of metamorphic triple-junction solar cells grown on Ge (001) substrates. The solar cells investigated involve an In0.67Ga0.33P top cell, an In0.17Ga0.83As middle cell, and a Ge bottom cell. A graded buffer layer is inserted between the bottom and middle cells for the purpose of accommodating the lattice mismatch. Linearly-graded, step-graded, and S-graded compositional profiles were considered for this buffer layer. The x-ray rocking curve analysis for a number of hkl reflections including 004, 113, 116, 044, 026, and 117 was conducted for the case of Cu Kα1 radiation. We show that the use of non-destructive x-ray analysis allows determination of the threading dislocation densities in the top two cells. In the cases of S-graded or step-graded buffer layers, the buffer threading dislocation density could also be estimated.

Removal of Silicone Oil From Intraocular Lens Using Novel Surgical Materials.

To design, fabricate, and evaluate novel materials to remove silicone oil (SiO) droplets from intraocular lenses (IOL) during vitreoretinal surgery. Three different designs were fabricated using soft lithography of polydimethylsiloxane (PDMS), three-dimensional (3D) inverse PDMS fabrication using water dissolvable particles, and atomic layer deposition (ALD) of alumina (Al2O3) on surgical cellulose fibers. Laboratory tests included static and dynamic contact angle (CA) measurements with water and SiO, nondestructive x-ray microcomputer tomography (micro-CT), and microscopy. SiO removal was performed in vitro and ex vivo using implantable IOLs and explanted porcine eyes. All designs exhibited enhanced hydrophobicity and oleophilicity. Static CA measurements with water ranged from 131° to 160° and with SiO CA approximately 0° in 120 seconds following exposure. Nondestructive x-ray analysis of the 3D PDMS showed presence of interconnected polydispersed porosity of 100 to 300 μm in diameter. SiO removal from IOLs was achieved in vitro and ex vivo using standard 20-G vitrectomy instrumentation. Removal of SiO from IOLs can be achieved using materials with lower surface energy than that of the IOLs. This can be achieved using appropriate surface chemistry and surface topography. Three designs, with enhanced hydrophobic properties, were fabricated and tested in vitro and ex vivo. All materials remove SiO within an aqueous environment. Preliminary ex vivo results were very promising, opening new possibilities for SiO removal in vitreoretinal surgeries. This is the first report of an instrument that can lead to successful removal of SiO from the surface of IOL. In addition to the use of this instrument/material in medicine it can also be used in the industry, for example, retrieval of oil spills from bodies of water.

Bendable 임베디드 전자모듈의 손상 메커니즘

A bendable electronic module has been developed for a mobile application by using a low-cost roll-to-roll manufacturing process. In flexible embedded electronic module, a thin silicon chip was embedded in a polymer-based encapsulating adhesive between flexible copper clad polyimide layers. To confirm reliability and durability of prototype bendable module, the following tests were conducted: Moisture sensitivity level, thermal shock test, high temperature & high humidity storage test, and pressure cooker tester. Those experiments to induce failure of the module due to temperature variations and moisture are the experiment to verify the reliability. Failure criterion was 20% increase in bump resistance from the initial value. The mechanism of the increase of the bump resistance was analyzed by using non-destructive X-ray analysis and scanning acoustic microscopy. During the pressure cooker test (PCT), delamination occurred at the various interfaces of the bendable embedded modules. To investigate the failure mechanism, moisture diffusion analysis was conducted to the pressure cooker's test. The hygroscopic characteristics of the encapsulating polymeric materials were experimentally determined. Analysis results have shown moisture saturation process of flexible module under high temperature/high humidity and high atmosphere conditions. Based on these results, stress factor and failure mechanism/mode of bendable embedded electronic module were obtained.

Nondestructive analysis by combined X-ray tomography on a synchrotron radiation facility

A nondestructive X-ray analysis technique combining transmission tomography, fluorescence tomography and Compton tomography based on synchrotron radiation is described. This novel technique will be an optional experimental technique at SSRF's hard X-ray micro-focusing beamline under construction at present. An experimental result of combined X-ray tomography is obtained in NE-5A station of PF. The reconstructed images of test objects are given.

Nondestructive X-ray analysis and petrophysical evaluation of a Cybele votive plaque

A votive plaque to Cybele, a unique stone monument from the Roman province of Thracia, was studied by nondestructive X-ray analysis and petrophysical methods (including free-water saturation and ultrasonic velocities) with the aim of determining the mechanical properties of the stone and the efficiency of the conservation procedures. It was shown that treatment with Paraloid B 72 toluol solution results in large increase in Young’s and shear modulus of the stone. The analysis of two supposedly detached fragments of the monument indicated that one of them is probably not part of the original material.

Pore structure of cement/pozzolan composites by X-ray microtomography

Microtomography, a nondestructive X-ray analysis test, was used to study the pore structure of cement/pozzolan composites. The three-dimensional picture of the overall porosity was created by stacking together sequential slices of two-dimensional microtomographic images. This picture revealed all the pores above 5 μm in diameter, showing that the largest pore was 0.5 mm in diameter and that the volume of large pores was around 2% by volume.

X-ray characterization of stacked InP/(InGa)As:C HBT and InP/(InGa)As HEMT layer sequences grown by LP-MOVPE using non-gaseous sources

Stacked layer sequences of InP-based HBT and HEMT are of interest for today's (OC-768) and tomorrows (OC-3072, 100 Gbit Ethernet) communication standards. The better low noise performance of the HEMT can be combined with the driver capability of the HBT while also a PIN-photodiode can be provided by the HBT base-collector-diode. However this results in a complex procedure for MOVPE growth process development. For a reliable fabrication of complex radio frequency (opto-)electronic circuit applications a quantitative InP process technology control is necessary starting at the level of device epilayer stacks. In this report the detailed characterization of stacked InP/(InGa)As:C HBT and InP/(InGa)As HEMT layer sequences is carried out by non-destructive X-ray analysis. Based on X-ray measurements in 004- and 002-reflection a detailed analysis of complex device layer stacks is purposed. As a result, an automatic calculation of layer parameters, e.g. thickness and composition is possible, reducing the turn-around time for the statistical process control (SPC).

The trials of wafer-scale integration : Jack F. McDonald, Edwin H. Rogers, Kenneth Rose and Andrew J. Steckl. IEEE Spectrum 32 (October 1984)

Stacked layer sequences of InP-based HBT and HEMT are of interest for today's (OC-768) and tomorrows (OC-3072, 100 Gbit Ethernet) communication standards. The better low noise performance of the HEMT can be combined with the driver capability of the HBT while also a PIN-photodiode can be provided by the HBT base-collector-diode. However this results in a complex procedure for MOVPE growth process development. For a reliable fabrication of complex radio frequency (opto-)electronic circuit applications a quantitative InP process technology control is necessary starting at the level of device epilayer stacks. In this report the detailed characterization of stacked InP/(InGa)As:C HBT and InP/(InGa)As HEMT layer sequences is carried out by non-destructive X-ray analysis. Based on X-ray measurements in 004- and 002-reflection a detailed analysis of complex device layer stacks is purposed. As a result, an automatic calculation of layer parameters, e.g. thickness and composition is possible, reducing the turn-around time for the statistical process control (SPC).

Improving bond yields to metal package leads : Doug Day. Semiconductor Int. 90 (July 1984)

Stacked layer sequences of InP-based HBT and HEMT are of interest for today's (OC-768) and tomorrows (OC-3072, 100 Gbit Ethernet) communication standards. The better low noise performance of the HEMT can be combined with the driver capability of the HBT while also a PIN-photodiode can be provided by the HBT base-collector-diode. However this results in a complex procedure for MOVPE growth process development. For a reliable fabrication of complex radio frequency (opto-)electronic circuit applications a quantitative InP process technology control is necessary starting at the level of device epilayer stacks. In this report the detailed characterization of stacked InP/(InGa)As:C HBT and InP/(InGa)As HEMT layer sequences is carried out by non-destructive X-ray analysis. Based on X-ray measurements in 004- and 002-reflection a detailed analysis of complex device layer stacks is purposed. As a result, an automatic calculation of layer parameters, e.g. thickness and composition is possible, reducing the turn-around time for the statistical process control (SPC).

Die bestimmung der Korngrösse der dünnen Aufdampfschichten aus der analyse von Röntgeninterferenzlinienprofilen

Resume The grain size in vacuum-deposited thin films has been studied by means of non-destructive X-ray analysis. Convolutory techniques after Jones and Stokes were applied, as the intensity of reflections in thin films is so low as to prevent detection of lines of high order ( nh, nk, nl ) as is required by the Warren-Averbach theory. An Au thin film, about 3000 A thick, was examined and a grain size S of 150±30 A was obtained from the analysis of the {422}-line profile. The algorithms used during analysis of the step-by-step recordings takes the specific properties of thin films into account, and can be used with success in general determination of grain size in thin films evaporated under vacuum with different parameters of deposition.