Differential time domain spectroscopy method for measuring thin film dielectric properties
US6556306B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 4, 2001 |
| Grant date | Apr 29, 2003 |
| Priority date | — |
| Expiry date | Jul 13, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/3586
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A non-contact, free-space method for determining the index of refraction of a thin film at a desired angular frequency. The method includes generating an input desired-frequency pulse and an optically detectable probe pulse. The thin film is moved in and out of the path of the input pulse, creating an output pulse that alternates between a transmitted signal, created when the film intercepts the input pulse path, and a reference signal, created when the sample is outside the input pulse path. The output pulse modulates the probe pulse, which is then detected with a photo detector, and the difference between the transmitted signal and the reference signal is calculated. The above steps are repeated over a plurality of delay times between the input pulse and the probe pulse until a complete field waveform of the differential signal is characterized. The index of refraction is calculated as a function of a ratio between the differential signal for the thin film and the reference signal. A complete field waveform of the reference signal may be characterized by repeating the above steps for a reference plate identical to the sample except having a non-transmissive film instead of the th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.