Bulletin of the American Physical Society
APS March Meeting 2019
Volume 64, Number 2
Monday–Friday, March 4–8, 2019; Boston, Massachusetts
Session A23: Advanced Nanolithography and Machine LearningFocus
|
Hide Abstracts |
Sponsoring Units: GIMS Room: BCEC 158 |
Monday, March 4, 2019 8:00AM - 8:36AM |
A23.00001: Single Atom Scale Manipulation of Matter by Scanning Transmission Electron Microscopy Invited Speaker: Stephen Jesse tbd |
Monday, March 4, 2019 8:36AM - 8:48AM |
A23.00002: Automation of Atom-Scale Device Patterning using Machine Learning Jeremiah Croshaw, Mohammad Rashidi, Kieran Mastel, Marcus Tamura, Hedieh Hosseinzadeh, Robert A Wolkow In recent years, research involving dangling bonds (DBs) patterned on hydrogen-terminated silicon (H-Si) has reached several significant benchmarks, including their applications as logic gates, binary wires1 and rewritable memory2. These newly developed devices show promise for the implementation of atom scale DB circuitry. As device applications become realizable, automation of device fabrication is necessary to facilitate the transition to commercial applications. We show that by incorporating a deep neural network in our patterning process, we can greatly reduce the amount of active user time needed for device fabrication. Semantic segmentation is used with a convolution-deconvolution network to properly map and label surface defects. By combining this neural network with libraries from a commercial scanning probe microscope controller and a previously implemented probe tip conditioning suite3, complete automation of the patterning process is realized. |
Monday, March 4, 2019 8:48AM - 9:00AM |
A23.00003: Reduced Damage Electron Microscopy with Conditional Sample Re-illumination Akshay Agarwal, Yuri van Staaden, Vivek Goyal, Karl K Berggren We propose and theoretically analyze an electron microscopy scheme based on multiple sample illuminations with a very low current beam, in combination with Elitzur and Vaidman’s interaction-free measurement scheme. Our analysis starts with a prior guess for the characteristic transparency of each pixel on the sample. We update these priors after each round of illumination based on the statistics at the imaging detectors. The re-illumination for a pixel ceases once a stopping criterion is met. This criterion could be based on either a minimum required signal-to-noise-ratio, or a maximum imaging time. We show that this scheme reduces the damage suffered by the sample during imaging, compared to a conventional imaging scheme without conditional re-illumination. We calculated the maximum resolution at a given sample damage and signal-to-noise ratio that could be obtained with this scheme. This resolution shows an improvement over that from conventional imaging. We are working towards implementing this scheme on a scanning electron microscope, modified to include bright- and dark-field transmission electron detectors, and a fast beam blanker to obtain extremely low-dose electron pulses. |
Monday, March 4, 2019 9:00AM - 9:12AM |
A23.00004: In situ observation of Sb2S3 single crystal formation in glass by micro x-ray diffraction Courtney Au-yeung, Camelia Stan, Nobumichi Tamura, Himanshu Jain, Volkmar R G Dierolf Single crystal architectures in glass can be formed by a solid-solid transformation via localized heating by a laser or x-ray beam. As a result of the confined environment and the asymmetry of the boundary conditions close to the surface new phenomena such as a rotating crystal lattice are observed. This novel form of a crystals can offer new functionalities in micro/nano-opto-electro-mechanical systems. To understand the process of lattice formation that proceeds via crystal growth, we have observed in situ Sb2S3 crystal formation under x-ray irradiation. In these experiments, an x-ray beam is used as the heating source to fabricate the crystal structures while Laue diffraction patterns are collected at the same time. We explore the earliest stages of crystallization in this model system wherein glass transforms into single crystal without any change in local composition or long-range diffusion. The implications of these observations for the origin of the lattice rotation and crystal growth in a confined medium will be discussed. |
Monday, March 4, 2019 9:12AM - 9:24AM |
A23.00005: Characterization of stress induced by Si1-xGex in the active epitaxial film on a SOI substrate via Scanning Surface PhotoVoltage Microscopy. James Slinkman, Daminda Dahanayaka, Philip Kaszuba, Leon Moszkowicz, Randall Wells, Lloyd Bumm The mobility and breakdown voltage of field-effect transistors fabricated on a Silicon-on-Insulator substrate can be improved by embedding a Si1-xGex layer in the active epitaxial silicon layer1. The choice of the Ge fraction, x, dictates the mobility improvement due to band-bending proportionate to misfit strain. The thickness of the embedded Si1-xGex layer, modulates associated stress relaxation, the density of extended defects, and degree of amorphozation of the epitaxy. Techniques such as TEM and Raman spectrosopy are traditionally used to characterize the film stress state in such heterostructures. We present here a systematic study of the evolution of the stress state and relaxation as a function of the Si1-xGex layer thickness in the active epitaxy on production SOI wafers using a novel technique, Scanning Surface PhotoVoltage Microscopy (SSPVM). These results are correlated with those obtained by Raman spectroscopy. Some advantages of the use of SSPVM are noted, as well other uses of it for semiconductor characterization. |
Monday, March 4, 2019 9:24AM - 9:36AM |
A23.00006: Artificial Neural Networks for Analysis of Coherent X-Ray Diffraction Images Daniel Abarbanel, Mark Sutton, Hong Guo We present an application of neural networks to the analysis of diffraction images produced via X-ray photon correlation spectroscopy (XPCS) experiments. The detection apparatus for these experiments is an array of charge-coupled devices (CCDs). Determining the incident location of each photon allows for estimation of the image contrast, which elucidates structural and dynamical properties of a measured system such as diffusion constant and particle radius. Photons incident on the detector in the same vicinity result in additive interference that obscures their individual locations. A neural network classifier was designed and trained on data from an artificial model to scan an image and determine a discrete probability distribution for the number of photons that have been incident within the area of each CCD. These distributions were fit to the contrast and were found to be in agreement with the true underlying value. We have thus demonstrated a promising method for accurately determining the contrast from experimental XPCS images. |
Monday, March 4, 2019 9:36AM - 9:48AM |
A23.00007: 2-beam action spectroscopy for probing multiphoton absorption processes in semiconductors Nikolaos Liaros, Daniel Jovinelli, John T Fourkas We recently introduced a new class of methods, called two-beam action (2-BA) spectroscopies for determining the order of effective absorptive nonlinearity in different materials. The 2-BA spectroscopy approach offers significant advantages over traditional logarithmic plots of an observable as a function of average excitation power, particularly when multiple orders of absorption are involved. In this work, we extend the 2-BA concept in a technique that we call 2-beam constant-amplitude photocurrent spectroscopy (2-BCAmP). We use this technique to study multiphoton absorption in wide-bandgap semiconductors. 2-BCAmP allows us for the measurement of the effective order of the absorption process at any desired value of the photocurrent or photovoltage, as opposed to traditional approaches that require data that span several orders of magnitude of average excitation power. Furthermore, the relative contributions of two different absorption orders can be extracted from non-integral 2-BCAmP exponents, and these data to validate the model of the absorption orders that are involved in photocurrent generation. |
Monday, March 4, 2019 9:48AM - 10:00AM |
A23.00008: High-Resolution Localization with Arbitrary Point Spread Functions Rohan Parab, Craig Snoeyink We present a method of three dimensional localization of particles which is agnostic to point spread functions and which achieves high localization resolution. By learning the spatial variation of the imaging system's point spread function using computationally efficient spline surfaces it is possible to utilize convex expectation-maximization localization methods with any imaging system. Perhaps more importantly, this methodology allows for the use of common localization point spread functions (Astigmatism, Double-Helix, Bessel Beam among others) but where strong aberrations might have precluded measurements. In addition to the method we will present experimental results comparing the resolution of this technique to localization where the point spread function is well known. |
Monday, March 4, 2019 10:00AM - 10:12AM |
A23.00009: Development of in-situ RF-enabled high-brightness femtosecond electron microscopy for complex material research Shuaishuai Sun, Xiaoyi Sun, Daniel Bartles, Elliot D Wozniak, Joseph Williams, Faran Zhou, Nelson Sepulveda, Chong-yu Ruan Correlated structural and electronic degrees of freedom in electronic materials help engineer macroscopic functional responses to external control parameters. Increasingly, new functionalities have been explored through integrating different electronic materials to form hybrid interfaces. Spatially and temporally resolved imaging and spectroscopy probe could provide a new perspective to study functionalities in ever increasing complexity in these new material platforms. However, significant challenges exist in reaching adequate sensitivities at the ultrafast timescale and nanometer spatial scale. Here we report a new development of ultrafast in-situ electron microscopy to address this limitation through active control of high-intensity femtosecond electron pulses, targeting the respective probe space using adaptive optics. An integrated system with compact DC gun, RF compression optics, and commercial TEM electron optics is established with the aim of nanometer-scale selected area imaging and core-level spectroscopy with combined ~100 femtosecond and ~1 eV resolution. We demonstrate our first application in studying the inhomogeneous phase transitions in VO2 microelectronic devices. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700