Optical monitoring of semiconductor growth processes

1
Optical monitoring of semiconductor growth
processes
Proposal for transfer to PhD register

• Francis Pedreschi

Supervisor Dr J.D. OMahony
2
Aims of Project

• Develop a system for monitoring the growth of
  semiconductors
• To use this system to examine certain test systems

3
Why?

• Growth of semiconductors must be monitored and
  controlled.
• Semiconductor device miniaturisation.
• Current methods may be destructive on small scale.

4
Current monitoring methods

• Electron beam techniques.
• Surface specific.
• High energy electrons.
• Cumbersome equipment.
• Difficult to get surface specificity with optical
  probes

5
Reflectance Anisotropy Spectroscopy

• Measures reflectivity of polarised light along
  two directions and reports the difference.
• Directions are chosen so bulk reflectivity is
  largely negated.

6
Examples

• Growth Oscillations, fixed energy

7
Examples

• Variable energy

8
Model systems for testing.

• Must mimic application conditions.
• Small structures.
• Interesting Physics

9
Results
10
Results
11
Results

• Largest published RAS response for a
  metal-semiconductor system.
• Indicates electron localisation.
• Demonstrates growth monitoring

12
Extension to PhD.

• Low dimensional systems.
• Unusual properties.
• Characterise using a variety of methods.
• Unfinished work on indium-silicon systems

13
Indium-Silicon

• RAS has already been performed on other indium
  silicon systems.
• These have not been extensively studied.
• RAS and photoemission.

14
Other Systems

• Ordered arrays of metal particles.
• Iron particles produced locally.
• Cobalt clusters produced by IBM.

15
Iron Particles

• Structure

• Films

Metal Particle
Polymer Coating
16
Cobalt Particles

• Particles difficult to produce

• Form well ordered films

17
Reasons for Study

• Properties of low dimensional systems.
• Magnetic properties-IBM.
• Magnetic storage media.
• Read/write heads.
• Complementary work.

18
Methods

• RAS?
• Ellipsometry
• Magneto Optical Kerr Effect
• Magnetic Circular X-Ray Dichroism
• Atomic Force Microscopy
• Magnetic Force Microscopy

19
Facilities.

• RAS in DIT and Liverpool
• Metal Particles in TU Eindhoven
• MCXD in Hamburg

20
Timeplan for project

• Work in Eindhoven completed by December 1999
• Work in IRCSS Liverpool performed early 2000

21
Summary

• RAS successfully demonstrated.
• Funding and facilities for project extension.
• Work of practical interest.
• Should be completed within 18 month time limit.