Optical apparatus and method for measuring temperature of a substrate material with a temperature dependent band gap
US5388909A · kind A · utility
Inventors
Key dates
| Filing date | Sep 16, 1993 |
| Grant date | Feb 14, 1995 |
| Priority date | — |
| Expiry date | Sep 16, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K11/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical method and apparatus for measuring the temperature of a substrate material with a temperature dependent bandgap. The substrate is illuminated with a broad spectrum lamp and the bandgap is determined from the spectrum of the diffusely scattered light. The spectrum of the light from the lamp is sufficiently broad that it covers the spectral range above and below the bandgap of the substrate. Wavelengths corresponding to photon energies less than the bandgap of the substrate are transmitted through the substrate and are reflected from the back surface of the substrate as well as from the front surface while the wavelengths corresponding to photon energies larger than the bandgap are reflected only from the front surface. If the front surface is polished the front surface reflection will be specular while if the back surface is rough the reflection from the back surface will be non-specular. The back surface reflection is detected with a detector in a non-specular location. From the wavelength of the onset of the non-specular reflection the bandgap can be determined which gives the temperature. The temperature is determined from the knee in the diffuse reflectance spectrum n…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.