It depends on light beam dimensions. Typically 5*5 mm2 is enough for any ellipsometer. But some models are able to measure in 60 um * 60 um area

Thank you so much.How about the Sample thickness ?

spectroscopic ellipsometry works well for submicron thickness films. For inspection spot size we used to turn the room lights down and put a business card on the sample stage, then we could see the spot.

Thickness between 70 nm and 1 um are best for spectroscopic ellipsometers in visible wavelength range. Higher thickness is possible if sample quality is very good and thickness is VERY uniform over the spot. A good estimate for the refractive index is useful.

For lower thickness single wavelength ellipsometers are more appropriate. Silicon wafers as substrate is recommended.

X*Y dimension case 1 cm X 1 cm will be better.

The one we use has a beam spot size of 1mm sq. So for this case we can use any size sample that can be properly located at the position where the beam hits.

For the size of the sample itself you can measure any size you want but you should tell what SE you have. for me I used M-2000 and the size could be 1"x1" to 6" x 6" while when I use Acuumap M-2000, I can measure 1x1 m2.