Nanolithography of SiOxide With an Atomic Force Microscope

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Nanolithography of Si-Oxide With an Atomic Force
Microscope

• Name Suzie Harvey
• Level Senior
• Number of Semesters Participated 2
• Date of Submission
• Advisor Dr. Rudy Schlaf
• Department Electrical Engineering

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Introduction
Introduction

• Nanolithography
• The process of creating nano-sized patterns on
  a surface.
• In our experiments the AFM was used to create
  nano-oxide patterns on silicon
• Preparation
• The silicon is etched in hydrofluoric acid to
  remove native oxide layer, and passivate the
  surface with hydrogen atoms.
• Patterns are written in Visual C, then loaded
  into the AFM Controller, which converts the lines
  of code into instructions for the AFM.

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Methodology
Methodology

• Oxidation of Silicon
• Oxidation occurs naturally when the silicon is
  exposed to air
• By applying an voltage to the tip of the
  cantilever, an electric field is created between
  tip and sample, accelerating the oxidation
  process.
• Oxidation Patterns
• The AFM controller converts the lines of c
  code into instructions for the AFM.
• As the tip moves across the surface, oxidation
  occurs, creating a raised oxide pattern.
• Creating Patterns in DesignCAD
• Until now, each new pattern had to be written up
  in c
• Patterns may now be easily drawn in DesignCAD
• The program I wrote converts the DesignCAD file
  into the proper c format
• The new program saves time, and is user-friendly

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Results
Results

• Diamond Test Pattern
• Oxidation of Silicon wafer
• Tip Voltage 10v
• Write Speed 0.5µm/s
• Amplitude Setpoint .04
• Oxidation thickness approx. 2nm.
• Dimensions of diamond are approx 7µm7µm.

• NNRC Pattern
• Oxidation of silicon wafer
• Tip Voltage 10v
• Write Speed 0.5µm/s
• Setpoint Factor .02
• Oxidation thickness lt 1nm.
• Dimensions of letters approx. 2µm3µm