Modeling of Joule heating and thermoelectric transport in thin film silicon for SJEM measurement

Koh, Youngjoon

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https://hdl.handle.net/2142/49679 Copy

Description

Title

Modeling of Joule heating and thermoelectric transport in thin film silicon for SJEM measurement

Author(s)

Koh, Youngjoon

Issue Date

2014-05-30T17:04:23Z

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
• Thermoelectric effect
• Joule heating
• COMSOL
• Thin film Si

Abstract

This thesis reports the finite element modeling of a quantitative nanometer-scale temperature distribution along the doped Si devices. The modeling replicates data acquisition technique of Scanning Joule expansion microscopy (SJEM). Time varying heat equations and Maxwell’s equations are solved in frequency domain and applied to commercial finite element software, COMSOL. Chapter 1 introduces various techniques to obtain nanoscale temperature distribution. In Chapter 2, Joule heating and Thermoelectric heating in 1st harmonic and 2nd harmonic signals are analyzed by comparing the terms in governing equations and simulation results. Chapter 3 optimizes device design of doped Si and experimental conditions for future measurement. The approach used in Chapter 2 is expanded in Chapter 4 to understand thermoelectric behaviors in 500 nm thick boron doped p-type and phosphorus doped n-type Si devices with doping levels of 1019 cm-3 and 1018 cm-3. PtSi or NiSi Ohmic contacts are formed on the devices and thermoelectric behaviors are analyzed in conditions either under simultaneous DC and AC excitations, or AC only excitations. The simulation results show that thermoelectric contribution in heating increases with the product of electrical conductivity and Seebeck coefficient. Chapter 5 explains the future plan for the device fabrication and platform for contact resistance measurements. The studies in this thesis can extend to Schottky contact devices and further complicated structures for understanding heat and thermoelectric transport in specific frequency.

Graduation Semester

2014-05

Permalink

http://hdl.handle.net/2142/49679

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Copy right 2014 Youngjoon Koh

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