Abstract
The lateral resolution of scanning thermal microscopy (SThM) has hitherto never approached that of mainstream atomic force microscopy, mainly due to poor performance of the thermal sensor. Herein, we report a nanomechanical system-based thermal sensor (thermocouple) that enables high lateral resolution that is often required in nanoscale thermal characterization in a wide range of applications. This thermocouple-based probe technology delivers excellent lateral resolution (∼20 nm), extended high-temperature measurements >700 °C without cantilever bending, and thermal sensitivity (∼0.04 °C). The origin of significantly improved figures-of-merit lies in the probe design that consists of a hollow silicon tip integrated with a vertically oriented thermocouple sensor at the apex (low thermal mass) which interacts with the sample through a metallic nanowire (50 nm diameter), thereby achieving high lateral resolution. The efficacy of this approach to SThM is demonstrated by imaging embedded metallic nanostructures in silica core-shell, metal nanostructures coated with polymer films, and metal-polymer interconnect structures. The nanoscale pitch and extremely small thermal mass of the probe promise significant improvements over existing methods and wide range of applications in several fields including semiconductor industry, biomedical imaging, and data storage.
Original language | English (US) |
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Pages (from-to) | 1760-1767 |
Number of pages | 8 |
Journal | ACS nano |
Volume | 12 |
Issue number | 2 |
DOIs | |
State | Published - Feb 27 2018 |
Funding
This work made use of the SPID facilities of the NUANCE Center at Northwestern University which has received support from Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF-ECCS-1542205), MRSEC program (NSF DMR-1121262) at the Materials Research Center, the International Institute for Nanotechnology (IIN), the Keck Foundation, and the State of Illinois, through the IIN. This work was supported by grants from the National Science Foundation award number 1256188, IDBR: Development of Higher Eigen mode Ultrasound Bioprobe for Sub-Cellular Biological Imaging. We thankfully acknowledge NSF SBIR grant (1256640) awarded to APPNANO for the development of VertiSense SThM technology. S.K. would like to acknowledge the support from Canada Research Chairs (CRC) program and the Natural Sciences and Engineering Research Council of Canada (NSERC).
Keywords
- STHm
- VertiSense
- metallic nanostructures
- nanomechanical thermal sensor
- temperature mapping
- thermal conductivity mapping
- thermal imaging
ASJC Scopus subject areas
- General Materials Science
- General Engineering
- General Physics and Astronomy