On-Chip 4f-System-Based Arbitrary-Mode Spot Size Conversion

X-ray diffraction(XRD) from polycrystalline materials is a powerful structural probe, capable of obtaining information on phase(s), crystallite orientation, average grain size, and residual stress. One problem in the application of XRD to the analysis of semiconductor chips and multi-chip carriers is that there is often the need to obtain information from individual features, which can range in size from several hundred microns on chip carriers to sub-micron on semiconductor devices. Conventional powder diffractometers are designed to irradiate an area of several square millimeters, and cannot be used to examine individual micron-sized features. This need to obtain diffraction information from very small areas has been one of the driving forces behind the development of x-ray microbeam diffraction.The design of a microdiffractometer involves modification of the incident x-ray beam, the sample holder, and the x-ray detector. The incident beam must be focused down to a spot size consistent with the feature to be examined.

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Characterization of Dynamic Laser Stimulation Approach to Locate Memory Fails Using EeLADA

ISTFA 2017: Conference Proceedings from the 43rd International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2017p0184 ◽

2017 ◽

Author(s):

S.H. Goh ◽

B.L. Yeoh ◽

Y.T. Ngow ◽

Hu Hao ◽

Alan Tan ◽

...

Keyword(s):

Spot Size ◽

Embedded Memory ◽

Self Testing ◽

Modern System ◽

On Chip ◽

Electrically Enhanced ◽

Embedded Memories ◽

Reduced Power Consumption ◽

Subsequent Failure

Abstract Most modern system on-chip incorporates a significant amount of embedded memories to achieve a reduced power consumption, higher speed and lower cost. In general, such memories are evaluated using built-in self-testing methods and in the event of a failure, bitmapping is heavily relied on for fault localization to guide subsequent failure analysis. However, a fast yield ramp can be impeded when bitmapping is not enabled in time or is inaccurate. This work studies the feasibility of employing electrically-enhanced LADA as an alternative method to debug embedded memory failures. Results are presented to demonstrate that the resolution of localization depends on the precision of diagnostic test pattern used and the laser spot size.

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On-chip arbitrary-mode spot size conversion

Nanophotonics ◽

10.1515/nanoph-2020-0328 ◽

2020 ◽

Vol 9 (14) ◽

pp. 4365-4372

Author(s):

Wei Qi ◽

Yu Yu ◽

Xinliang Zhang

Keyword(s):

Spot Size ◽

Expansion Ratio ◽

Fourier Optics ◽

Graded Index ◽

Beam Expander ◽

Single Lens ◽

Optical Modes ◽

On Chip ◽

Integrated Device ◽

F System

AbstractManipulating on-chip optical modes via components in analogy with free-space devices provides intuitional light control, and this concept has been adopted to implement single-lens–assisted spot size conversion using integrated device. However, the reported schemes have been demonstrated only for fundamental mode, while high-order or irregular modes are preferred in specific applications. The 4-f system is widely used in Fourier optics for optical information processing. Under the inspiration of the 4-f system and the beam expander in bulk optics, a spot size converter (SSC) with two metamaterial-based graded-index waveguides is proposed and demonstrated. The proposed device is capable of widening an arbitrary mode while preserving its profile shape. Compared with conventional SSC using adiabatic taper, the footprint can be reduced by 91.5% under a same intermode crosstalk. Experimentally, an expansion ratio of five is demonstrated for regular modes. Furthermore, for an irregular mode, the functionality is numerically verified without structure modification. This work offers a universal solution to on-chip spot size conversion and may broaden the on-chip application prospects of Fourier optics.

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On-chip THz spectrometer for bunch compression fingerprinting at fourth-generation light sources

Journal of Synchrotron Radiation ◽

10.1107/s1600577518010184 ◽

2018 ◽

Vol 25 (5) ◽

pp. 1509-1513

Author(s):

M. Laabs ◽

N. Neumann ◽

B. Green ◽

N. Awari ◽

J. Deinert ◽

...

Keyword(s):

Schottky Diode ◽

Simultaneous Detection ◽

Spot Size ◽

Center Frequency ◽

Fourth Generation ◽

Thz Radiation ◽

Light Sources ◽

Bunch Compression ◽

On Chip ◽

5 Ghz

The layout of an integrated millimetre-scale on-chip THz spectrometer is presented and its peformance demonstrated. The device is based on eight Schottky-diode detectors which are combined with narrowband THz antennas, thereby enabling the simultaneous detection of eight frequencies in the THz range on one chip. The size of the active detector area matches the focal spot size of superradiant THz radiation utilized in bunch compression monitors of modern linear electron accelerators. The 3 dB bandwidth of the on-chip Schottky-diode detectors is less than 10% of the center frequency and allows pulse-resolved detection at up to 5 GHz repetition rates. The performance of a first prototype device is demonstrated at a repetition rate of 100 kHz at the quasi-cw SRF linear accelerator ELBE operated with electron bunch charges between a few pC and 100 pC.

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Remarks on the application of backscattered electron imaging (BEI) to the scanning electron microscopy (SEM) of biological structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100076159 ◽

1983 ◽

Vol 41 ◽

pp. 484-487

Author(s):

Etienne de Harven

Keyword(s):

High Resolution ◽

Incident Beam ◽

Spot Size ◽

Primary Electron ◽

Critical Point Drying ◽

Cell Shapes ◽

High Resolution Images ◽

Backscattered Electron ◽

Electron Imaging ◽

Scanning Electron

Biological ultrastructures have been extensively studied with the scanning electron microscope (SEM) for the past 12 years mainly because this instrument offers accurate and reproducible high resolution images of cell shapes, provided the cells are dried in ways which will spare them the damage which would be caused by air drying. This can be achieved by several techniques among which the critical point drying technique of T. Anderson has been, by far, the most reproducibly successful. Many biologists, however, have been interpreting SEM micrographs in terms of an exclusive secondary electron imaging (SEI) process in which the resolution is primarily limited by the spot size of the primary incident beam. in fact, this is not the case since it appears that high resolution, even on uncoated samples, is probably compromised by the emission of secondary electrons of much more complex origin.When an incident primary electron beam interacts with the surface of most biological samples, a large percentage of the electrons penetrate below the surface of the exposed cells.

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A High Resolution Scanning Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101529 ◽

1968 ◽

Vol 26 ◽

pp. 356-357

Author(s):

A. V. Crewe ◽

J. Wall ◽

L. M. Welter

Keyword(s):

High Resolution ◽

Field Emission ◽

Spherical Aberration ◽

Focal Length ◽

Spot Size ◽

Emission Source ◽

Field Of View ◽

Scanning Microscope ◽

Magnetic Lens ◽

High Quality

A scanning microscope using a field emission source has been described elsewhere. This microscope has now been improved by replacing the single magnetic lens with a high quality lens of the type described by Ruska. This lens has a focal length of 1 mm and a spherical aberration coefficient of 0.5 mm. The final spot size, and therefore the microscope resolution, is limited by the aberration of this lens to about 6 Å.The lens has been constructed very carefully, maintaining a tolerance of + 1 μ on all critical surfaces. The gun is prealigned on the lens to form a compact unit. The only mechanical adjustments are those which control the specimen and the tip positions. The microscope can be used in two modes. With the lens off and the gun focused on the specimen, the resolution is 250 Å over an undistorted field of view of 2 mm. With the lens on,the resolution is 20 Å or better over a field of view of 40 microns. The magnification can be accurately varied by attenuating the raster current.

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Image registration with a computer driven S.T.E.M.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107630 ◽

1978 ◽

Vol 36 (1) ◽

pp. 98-99

Author(s):

A.M.H. Schepman ◽

J.A.P. van der Voort ◽

J.E. Mellema

Keyword(s):

Spot Size ◽

Scanning Transmission Electron Microscope ◽

Small Computer ◽

Structural Studies ◽

Area Of Interest ◽

Transmission Electron ◽

Scanning Transmission ◽

Specimen Area ◽

On Line ◽

Minimum Distances

A Scanning Transmission Electron Microscope (STEM) was coupled to a small computer. The system (see Fig. 1) has been built using a Philips EM400, equipped with a scanning attachment and a DEC PDP11/34 computer with 34K memory. The gun (Fig. 2) consists of a continuously renewed tip of radius 0.2 to 0.4 μm of a tungsten wire heated just below its melting point by a focussed laser beam (1). On-line operation procedures were developped aiming at the reduction of the amount of radiation of the specimen area of interest, while selecting the various imaging parameters and upon registration of the information content. Whereas the theoretical limiting spot size is 0.75 nm (2), routine resolution checks showed minimum distances in the order 1.2 to 1.5 nm between corresponding intensity maxima in successive scans. This value is sufficient for structural studies of regular biological material to test the performance of STEM over high resolution CTEM.

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Ultra-spatially resolved synchrotron powered FT-IR microspectroscopy of individual cells of biological material

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100140798 ◽

1995 ◽

Vol 53 ◽

pp. 884-885

Author(s):

David L. Wetzel ◽

John A. Reffner ◽

Gwyn P. Williams

Keyword(s):

Thermal Noise ◽

Spot Size ◽

Acquisition Time ◽

Thermal Source ◽

Signal To Noise ◽

Spatially Resolved ◽

Good Spatial Resolution ◽

Small Spot ◽

Ft Ir ◽

Ir Microspectroscopy

Synchrotron radiation is 100 to 1000 times brighter than a thermal source such as a globar. It is not accompanied with thermal noise and it is highly directional and nondivergent. For these reasons, it is well suited for ultra-spatially resolved FT-IR microspectroscopy. In efforts to attain good spatial resolution in FT-IR microspectroscopy with a thermal source, a considerable fraction of the infrared beam focused onto the specimen is lost when projected remote apertures are used to achieve a small spot size. This is the case because of divergence in the beam from that source. Also the brightness is limited and it is necessary to compromise on the signal-to-noise or to expect a long acquisition time from coadding many scans. A synchrotron powered FT-IR Microspectrometer does not suffer from this effect. Since most of the unaperatured beam’s energy makes it through even a 12 × 12 μm aperture, that is a starting place for aperture dimension reduction.

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Electron Channelling Contrast Imaging of Dislocations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100181762 ◽

1990 ◽

Vol 48 (1) ◽

pp. 600-601

Author(s):

J.T. Czernuszka ◽

N.J. Long ◽

P.B. Hirsch

Keyword(s):

Field Emission ◽

Secondary Electron ◽

Surface Defects ◽

Spot Size ◽

Beam Divergence ◽

Contrast Imaging ◽

Scattered Electron ◽

Near Surface ◽

Filter System ◽

Electron Channelling

In the 1970s there was considerable interest in the development of the electron channelling contrast imaging (ECCI) technique for imaging near surface defects in bulk (electron opaque) specimens. The predictions of the theories were realised experimentally by Morin et al., who used a field emission gun (FEG) operating at 40-50kV and an energy filter such that only electrons which had lost no more than a few 100V were detected. This paper presents the results of a set of preliminary experiments which show that an energy filter system is unneccessary to image and characterise the Burgers vectors of dislocations in bulk specimens. The examples in the paper indicatethe general versatility of the technique.A VG HB501 STEM with a FEG was operated at 100kV. A single tilt cartridge was used in the reflection position of the microscope. A retractable back-scattered electron detector was fitted into the secondary electron port and positioned to within a few millimetres of the specimen. The image was acquired using a Synoptics Synergy framestore and digital scan generator and subsequently processed using Semper 6. The beam divergence with the specimen in this position was 2.5 mrads with a spot size of approximately 4nm. Electron channelling patterns were used to orientate the sample.

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