Rotating-compensator ellipsometer
US4053232A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 28, 1975 |
| Grant date | Oct 11, 1977 |
| Priority date | — |
| Expiry date | Apr 28, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/272
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Plane polarized light is reflected from a surface of a sample film to produce an elliptically polarized reflected beam. The reflected beam is passed sequentially through a rotating one-quarter wave plate and a fixed analyzer which transmits a beam whose intensity varies as a function of the rotational angle of the plate. The transmitted beam impinges upon a photodetector which produces an electric signal proportional to the intensity of the transmitted light. The rotating one-quarter wave plate cyclically varies the polarization of the beam, so that the electrical signal, when numerically Fourier analyzed, provides Fourier coefficients having both sin .DELTA. and cos .DELTA. terms, where the ellipsometric parameter .DELTA. is the instantaneous phase difference between the parallel (R.sub.p) and perpendicular (R.sub.s) components of the electric vector of the elliptically polarized reflected beam; therefore, the phase difference .DELTA. is uniquely and unambiguously defined in a single measurement. Furthermore, the presence of both sin .DELTA. and cos .DELTA. terms permits .DELTA. to be determined more accurately than is possible with the prior art rotating-analyzer ellipsometer. Si…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.