Protocols - SOPs

Ellipsometry (Rudolph Research AutoEL II)

1. Turn on the machine and follow the instructions on the display and place the sample.

2. Adjust the height of the sample bench using the Allan wrench till you don’t see the laser light on the detector.

3. Rotate three screws till the bright circle gets centered in the eye piece. Adjust the three screws at the same time and not all three screws should either be too tight or too lose.

4. Calibrate using the calibrating Si wafer. If you don’t get the right delta and psi values, change the location of the Si wafer you are looking at.

5. To make the measurement, hit “program → 210 → E”.

6. You see the delta and psi values on the screen.

Calculating the thickness of a single (1st) layer in ellipsometry

1. Open the “Mathcad Professional” and open the file “single layerSi.mcd” and modify the “refraction index Si oxide” depending on what layer has been deposited.

2. To track the curve, click on the curve → trace → click anywhere on the curve.

3. Count number of steps you have to move from the delta and psi values before deposition the layer to the delta and psi values after deposition.

4. Thickness of the layer = 5 (angstrom)* number of steps.

Calculating the thickness of a 2nd layer in ellipsometry (when two layers are deposited together)

1. Open the “Mathcad Professional” and open the file “Si–‐SiO2–‐SiN.mcd”.

2. Modify the refractive indices appropriately.

3. Modify the parameters in the graph (both on X–‐ and Y–‐axes) as well inserting the thickness of the 1st layer you calculated before.

4. As you did before, count the number of steps go from delta and psi values of 1st layer to that of 2nd layer.

5. Thickness of the 2nd layer = 5 (angstrom)* number of steps.

For emergency: contact Pradeep at 617–‐717–‐4024.