Emerging Materials and Processes (Academic Year 2021/22)
WEAR PROTECTIVE GEAR!! (LAB COAT; EYE PROTECTION GLASSES AND
GLOVES)
Lab_3 Elipsometry.
During this laboratory session, you will learn how to measure the thickness and refractive
index of organic thin films using an ellipsometer.
Data collected during this lab are part of the ‘Lab report’.
Elipsometry is a non-destructive, a non-invasive and non-contact optical analysis method,
which can be used to obtain various information such as layer thickness, refractive index
and absorption coefficient of a thin film. This technique can be used to examine samples
with nearly any size and shape. Both organic and inorganic thin films can be investigated
by elipsometry.
Exercise 1: Measure the thickness and refractive index of the PVAc thin film
Objective: During this exercise, you will learn how to measure the thickness and
refractive index of Polyvinyl acetate (PVAc) thin films on silicon substrate deposited
during Lab_3. Session.
Equipment: elipsometer and a pair of tweezers
Consumables: PVAc (10mg/ml; 25mg/ml) thin films (prepared in the lab_2)
Personal Protective Equipment (PPE): Lab coat, Gloves, Safety glasses
ELLIPSOMETER OPERATING INSTRUCTIONS:
These operating instructions are for automatic Ellipsometer Rudolf AutoEL III. This
Ellipsometer uses a red class 2 laser as a light source which is harmful to eyes. There
is nothing to worry about as the laser is fixed inside ellipsometer and during normal
operation there is no risk involve. But don’t try to look at the laser as even reflection can
be harmful. In order to operate ellipsometer. To take reliable measurements,
the
procedure listed below should be followed:
IF EQUIPMENT NOT SWITCHED ON:

If ellipsometer is not plugged in (which is unlikely), plug into wall mounted single
phase socket to the rear of the ellipsometer.
NOTE: IF YOU ARE UNSURE ABOUT WHAT TO DO, PLEASE DO NOT
PROCEED ANY FURTHER AND ASK A MEMBER OF STAFF TO PLUG IN THE
ELLIPOSMETER..

Turn on the electrical supply to the ellipsometer by turning the power key 2 position
switch (on the lower left hand side of the ellipsometer) anticlockwise to the ON
position.
NOTE: THE POWER INDICATOR WILL LIGHT AND THE DISPLAY WILL TURN
ON.

Check that after approximately 30 seconds, the ellipsometer display reads UP
COMP-INSERT SAMPLE-PRESS CONT.
NOTE: WAIT 15 MINUTES FROM THIS POINT TO ALLOW WARM UP OF THE
ELLIPSOMETER

The ellipsometer is now ready for experimental usage
NOTE: PLEASE BE AWARE THAT WHEN POWER IS TURNED ON TO THE
ELLIPSOMETER, A CLASS 2 HeNe LASER IS ALWAYS ON AND SO CARE
SHOULD BE TAKEN NOT TO REFLECT THE BEAM AWAY FROM THE SAMPLE
STAGE SO AS TO ENDANGER THE EYESIGHT OF YOURSELF OR OTHERS.
IF EQUIPMENT ON AND SAMPLES ARE READY FOR PLACEMENT ON SAMPLE
STAGE
1. Once the laser has warmed up you can proceed with ellipsometry
measurements. Ellipsometer allows measurements of thin film thickness and
refractive index of the film.
2. Press ‘Reset’ button if required. ‘Reset’ button should be pressed every time
sample type is changed.
3. Position sample on the measurement table.
4. Using eyepiece to align sample.
5. Look at the sensor aperture and confirm that laser beam enters sensor stage.
If not realign measurement table.
6. Follow instruction on screen
o
Slide compensator up and press ‘Cont’. Wait for the next command
o
Slide compensator down.
o
Press ‘Prog’.
o
On the keypad enter program number and press ‘E’. For a single layer
film on silicon programme 21 should be used.
o
Once measurements are finished, check the reading and record values
in your lab book.
7. If additional samples of the same type needed to be measured.
o
Change sample
o
Check sample alignment
o
Press ‘Cont’
o
Check readings and record data.
IF EQUIPMENT NEEDS TO BE SWITCHED OFF:

Remove the sample from the sample stage.

Press the compensator slide full down, if not already down.

Turn off the electrical supply to the ellipsometer by turning the power key 2 position
switch (on the lower left hand side of the ellipsometer) clockwise to the OFF position.
NOTE: THE DISPLAY AND POWER INDICATOR LIGHT WILL TURN OFF.

Turn off the power at the wall mounted mains electricity switch.

The ellipsometer has now been shut down safely
Figure 1. Schematic diagram of Ellipsometer Rudolf AutoEL III.
Before
to
test
your
sample(s),
check
that
ellipsometer
is
operating
correctly/calibrated by using a reference sample. You will find the Reference sample
next to the ellipsometer. Measure the reference sample following ellipsometer operating
instructions. Compare your data to calibration data for reference sample:


Thickness: 95 nm
Refractive index: 1.47
If measured data are within 1% of calibration data, then continue with experiment
otherwise report to the lab tutor or EMTERC technician.
Perform the measurements of PVAc thickness and refractive index for all deposited
samples and write down their values in the lab book. Check how the thickness/refractive
index of the film is influenced by deposition conditions – namely the spin speed. Plot the
collected data (thickness vs. spin speed) and comment on the results.
https://www.youtube.com/watch?v=2F4Gsqo-YvY
https://www.youtube.com/watch?v=BycPkRIutqg