Quantitative nanometer-scale thermal metrology using scanning joule expansion microscopy

Grosse, Kyle L.

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https://hdl.handle.net/2142/24392 Copy

Description

Title

Quantitative nanometer-scale thermal metrology using scanning joule expansion microscopy

Author(s)

Grosse, Kyle L.

Issue Date

2011-05-25T14:36:58Z

Director of Research (if dissertation) or Advisor (if thesis)

King, William P.

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• scanning Joule expansion microscopy (SJEM)
• atomic force microscope (AFM)
• Nanotechnology
• Temperature measurement
• Graphene
• hot spots
• contact effects
• microelectronics

Abstract

This thesis presents the development of a quantitative nanometer-scale thermal metrology technique, which is shown to obtain ~10 nm spatial and ~250 mK temperature resolution of the temperature rise of a graphene transistor. This is a large improvement over current state-of-the-art thermal metrology techniques which are on the order of 100 nm spatial and ~200 mK temperature resolution. The atomic force microscope (AFM) based thermal imaging technique is scanning Joule expansion microscopy (SJEM). SJEM operates by supplying a periodic voltage waveform to heat a sample, and the AFM measures the associated thermo-mechanical expansion of the surface. SJEM technique and artifacts are discussed to improve measurement accuracy, and a thermo-mechanical model is developed to correlate surface expansion to sample temperature. To demonstrate the capabilities of SJEM the temperature field of a graphene transistor and its contact to metal electrodes are measured. Thermal images reveal small ~100 nm diameter “hot spots” which exist on the graphene sheet, which are believed to be due to sample fabrication. Comparison of temperature measurements of graphene-metal contacts with a model of heat dissipation in graphene reveal that Joule heating, current crowding, and thermoelectric effects occur at the graphene contact. The agreement of the measurements with predictions demonstrates the high resolution capabilities of SJEM. The development of a quantitative nanometer-scale thermal measurement technique can have significant impacts on material characterization and the microelectronics industry.

Graduation Semester

2011-05

Permalink

http://hdl.handle.net/2142/24392

Copyright and License Information

Copyright 2011 Kyle Grosse

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