What does an ellipsometer measure?

What does an ellipsometer measure?

Ellipsometry measures a change in polarization as light reflects or transmits from a material structure. The polarization change is represented as an amplitude ratio, Ψ, and the phase difference, Δ. The measured response depends on optical properties and thickness of individual materials.

What is Psi and Delta in ellipsometry?

Psi and Delta represent the raw measurement from an ellipsometer. They describe the change in polarization that occurs when the measurement beam interacts with a sample surface. The incident light beam contains electric fields both parallel (p-) and perpendicular (s-) to the plane of incidence.

Who invented ellipsometry?

Paul Drude
The technique of ellipsometry was invented by Paul Drude in 1887 who used it to determine the dielectric function of various metals and dielectrics. For 75 years following Drude’s pioniering work only a handful of ellipsometric studies were done.

What is complex refractive index?

The complex refractive index m(λ) = mr(λ) + imi(λ), where λ is the free-space wavelength, mr is the real part of the refractive index, and mi is the imaginary part. The real part of a refractive index is the ratio of the free-space speed of light to the phase speed of an electromagnetic wave in the medium.

Which method is used to calibrate the thickness of SiO2 on SI?

Ellipsometric measurement of SiO2 layer on Si substrate Ellipsometry is an optical technique, which enables measurements of thickness and optical properties of thin films. In microtechnology it is commonly used to evaluate thickness of silicon oxide, silicon nitride, polysilicon, photoresist.

What types of thin film coatings can spectroscopic ellipsometry measure?

Ex-situ spectroscopic ellipsometry allows for the characterization of a range of thin film properties including layer thickness, surface roughness thickness, interface thickness, optical constants, composition, band gap, composition, crystallinity, grading, anisotropy, and uniformity by depth and area.

What Refractivity means?

: the ability of a substance to refract light expressed quantitatively specifically : the index of refraction minus one.

What are two types of reflexive index?

The refractive index is of two types:

  • Absolute Refractive Index.
  • Relative Refractive Index.

How do you analyze SiO2?

The SiO2 content is generally determined by a gravimetric method using hydrofluoric acid. Hydrofluoric acid is known for its ability to dissolve glass by reacting with SiO2 to form silicon tetrafluoride gas and hexafluorosilicic acid.

Why is silicon dioxide SiO2 layer used in ICs?

Silicon dioxide (SiO2) is used to mask the silicon surface during the diffusion or ion implantation process. The oxide layer is patterned by the photolithographic process.