Apparatus for measuring carrier lifetimes of a semiconductor wafer
US4581578A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1984 |
| Grant date | Apr 8, 1986 |
| Priority date | — |
| Expiry date | Jan 31, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S136/29
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A carrier lifetime measuring apparatus according to the present invention has a construction wherein a first photon beam of a wavelength capable of rendering the optical absorption coefficient of a semiconductor sample very small when the semiconductor sample having a potential barrier in the vicinity of its surface is irradiated with the radiation, and a second photon beam of a wavelength capable of rendering the optical absorption coefficient very large are respectively chopped to alternately irradiate the identical place of the semiconductor sample with the chopped beams; first and second photovoltages which are generated in the semiconductor sample by these photon beams are detected by capacitance coupling; and the ratio between a first amplitude variation and a second amplitude variation is obtained from the amplitudes of the detected photovoltages; thereby to evaluate a minority carrier lifetime in the semiconductor sample.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.