Method for determining the temperature of semiconductor substrates from bandgap spectra
US6116779A · kind A · utility
Inventors
Key dates
| Filing date | Mar 10, 1997 |
| Grant date | Sep 12, 2000 |
| Priority date | — |
| Expiry date | Mar 10, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K11/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical method for measuring the temperature of a substrate material with a temperature dependent band edge. In this method both the position and the width of the knee of the band edge spectrum of the substrate are used to determine temperature. The width of the knee is used to correct for the spurious shifts in the position of the knee caused by: (i) thin film interference in a deposited layer on the substrate; (ii) anisotropic scattering at the back of the substrate; (iii) the spectral variation in the absorptance of deposited layers that absorb in the vicinity of the band edge of the substrate; and (iv) the spectral dependence in the optical response of the wavelength selective detection system used to obtain the band edge spectrum of the substrate. The adjusted position of the knee is used to calculate the substrate temperature from a predetermined calibration curve. This algorithm is suitable for real-time applications as the information needed to correct the knee position is obtained from the spectrum itself. Using a model for the temperature dependent shape of the absorption edge in GaAs and InP, the effect of substrate thickness and the optical geometry of the method use…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.