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SURF: Announcements of Opportunity

Below are Announcements of Opportunity posted by Caltech faculty and JPL technical staff for the SURF program. Additional AOs for the Amgen Scholars program can be found here.

Specific GROWTH projects being offerred for summer 2019 can be found here.

Each AO indicates whether or not it is open to non-Caltech students. If an AO is NOT open to non-Caltech students, please DO NOT contact the mentor.

Announcements of Opportunity are posted as they are received. Please check back regularly for new AO submissions! Remember: This is just one way that you can go about identifying a suitable project and/or mentor.

Announcements for external summer programs are listed here.

Students pursuing opportunities at JPL must be
U.S. citizens or U.S. permanent residents.

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Project:  Sub-10 nm lithography of novel resist materials using a transmission electron microscope
Disciplines:  Applied Physics, Materials Science
Mentor:  Axel Scherer, Bernard Neches Professor of Electrical Engineering, (EAS), etcher@caltech.edu
Mentor URL:  http://nanofab.caltech.edu/members/2-axel-scherer.html  (opens in new window)
AO Contact:  Matthew S. Hunt, PhD, matthew.hunt@caltech.edu
Background:  The Scherer Group and the Kavli Nanoscience Institute (KNI) at Caltech are engaged in a collaboration with The University of Manchester to explore the limits of nanoscale fabrication using novel lithography materials and techniques. Recent work has resulted in the creation of sub-10 nm wide fins – of the type now commonly used in FinFET transistor technology – in both silicon and tungsten. This was done using a 35 keV helium ion beam for the lithographic exposure, high-resolution supramolecular resists synthesized at Manchester for the exposure material, and reactive-ion etching to transfer the pattern into the substrate; the work with helium ions surpassed what is achievable with traditional 100 keV electron beam lithography. In this project, the student will use a 200 keV electron beam on a transmission electron microscope (TEM) in an attempt to equal or further shrink the achievable feature size. This should be possible at such high energy because both (1) the beam diameter in the TEM can approach as small as 2 Å, better than the 4 Å of the helium ion microscope, and (2) the proximity effects that limit the size of nanostructures written with 100 keV electrons are expected to be reduced. Additionally, since a 200 keV beam cuts through the resist material with so little scattering, taller – not just smaller – structures are capable of being written. The ability to write ultra-high-aspect-ratio structures in resist may, in turn, lead to taller fins and, as a result, to other interesting nanoscale 3D printing possibilities.

While smaller (and in this case, taller, too) is often better in nanoscience, that is not the only motivation for employing a higher energy beam in this project. The PIs are also committed to understanding the mechanisms by which improvements in nanotechnology can be achieved, furthered and exploited. In this project, since these resist materials are cross-linked not only by their interaction with the incident beam, but primarily by the cascade of secondary electrons and Auger electrons that are created as a result of those initial interactions, being able to model the material’s behavior under exposures of 100 vs. 200 keV electrons – and then verify via experiment – can help elucidate the mechanisms by which the material works best. Crucially, understanding these mechanisms can lead to the design of better next-generation lithographic materials and, ultimately, to the creation new techniques and technologies.
Description:  The student will join the Scherer Group & the Kavli Nanoscience Institute (KNI) cleanroom and work with a Tecnai TF-20 200 keV TEM in Scanning probe (aka STEM) and/or microdiffraction mode to perform lithographic exposure experiments on the latest supramolecular resists that will have been manufactured by the Manchester group. In order to characterize the resultant nanostructures, the student will utilize scanning electron microscopy (SEM), helium ion beam microscopy (HIM), and even the TEM itself, in reflection electron microscopy (REM) mode. REM is an unconventional technique used for imaging thick samples with a TEM, which is otherwise predominantly used to study electron-transparent (i.e. less than 200 nm thin) materials, and a technique that Prof Scherer is eager to apply to sub-10 nm structures. The student will also be involved in modelling beam–specimen interactions using the latest Monte Carlo simulations, provided by the Manchester group, that calculate 4th order secondary and Auger electron generation. The simulation results will be compared with the experimental results to shed light on relevant atomic scale mechanisms. Finally, the student will use STEM lithography to pattern a field-emitter device that has been designed by the Scherer Group; this will provide the student with (1) an experience in cleanroom device fabrication and (2) an opportunity to make field emission measurements on something she/he created, using existing testing equipment in the Scherer Lab.

The student is expected to emerge from the summer having gained considerable experience in a range of microscopy and fabrication techniques, and will have also had a hand in advancing the simulation side of this ongoing collaboration between Caltech and Manchester. To accomplish the project, the student will be co-mentored by Prof Axel Scherer and the KNI’s Assistant Director of Staff Research and Lead Microscopist, Matthew Hunt, PhD. The student will also have the opportunity to work with Dr. Scott Lewis, the visiting collaborator from Manchester, who will be in the Scherer and KNI labs at the start of the summer. A selected Scherer Group graduate student will also be involved, helping the student on the modelling and device fabrication sides of the project.

***Note: Given that this is a collaboration with the KNI, the student who is chosen for the project will be considered for one of several KNI SURF-the-WAVE Fellowships. Read more about that program here: kni.caltech.edu/programs/surf-the-wave. Consider applying directly for a WAVE Fellowship – separate from or in addition to contacting this project’s co-mentors – if you meet criteria.***
References:  1. “Frontiers of Solid-State Physics,” an overview presentation by Dr. Scott Lewis on state-of-the-art lithography and resist technology, with a section on his Univ. of Manchester group’s supramolecular resist materials, slides 52-58 (http://bit.ly/2QHHTRT)

2. “Use of Supramolecular Assemblies as Lithographic Resists,” a 2017 publication from the Manchester–Caltech collaboration (http//bit.ly/2L8VMDo)

3. “Resolution Limits of Electron-Beam Lithography toward the Atomic Scale,” a 2013 publication by Manfrinato et al on STEM lithography of hydrogen silsesquioxane (HSQ), a commercially available resist (http://bit.ly/2L8GRsZ)

4. “Reflection Electron Microscopy (REM) of FCC Metals,” an early publication (1983) on the REM technique by Hsu & Cowley (http://bit.ly/2GbMzvf)
Student Requirements:  A coursework background in physics, materials science, chemistry, and/or engineering (e.g. electrical, mechanical, etc.) is appropriate.

An organized, detail-oriented approach to optimization is necessary for both fabrication and microscopy, the two main components of this project. Experience in coding would help on the modelling side.

The applicant would also benefit from prior experience with (but otherwise would receive expert, concentrated training in) micro/nanoscale characterization, e.g. scanning electron microscopy (SEM), transmission electron microscopy (TEM) and/or atomic force microscopy (AFM).
Programs:  This AO can be done under the following programs:

  Program    Available To
       SURF    both Caltech and non-Caltech students 

Click on a program name for program info and application requirements.


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