Previous Lecture - - - - Next Lecture
Thin Film Characterization - Optical Techniques
Ohring Chapter 6 Section 2.2
Use change of polarization of light reflected from a sample
Polarization of Light
We often use these to define reflection coefficients:
rp= Erp / Eip and rs = Ers / Eis
In ellipsometry we define two other parameters (psi and delta):
ellipsometry data depends on index of refraction of ambient medium (air), film(s) and substrate and thickness of film(s).
index is generally complex (real index and absorption) N = n - ik
single measurement of one film on substrate:
three unknown parameters (n, k, d of film)
two measurable parameters (psi and delta)
need to vary experimental parameters to obtain enough data to solve
Use measured data and layer model to determine optical properties and thickness of layers.
Then use EMA to determine porosity and roughness of layers.
use interference of beams of light with different optical paths to determine film thickness
© Thomas M. Christensen