Micro Photoreflectance Semiconductor Wafer Analyzer.
Patent Application, Filed 21 Dec 90,
DEPARTMENT OF THE NAVY WASHINGTON DC
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An apparatus for measuring local carrier concentration in a preselected area of a semi-conductor is shown and described. An exciting light preferably a laser alters the samples band-gap by photo injecting electron hole pairs in the area being measured. Because of the Franz-Keldysh effect, the photo injected carriers alter the samples reflectivity. An optical fiber conducts a broad band source of probing light to the excited area on the sample. The sample reflects some of the broad band light back into a fiber that conducts the reflected light to an optical analyzer. The optical analyzer includes a dispersive element that disperses the reflected light onto a linear array of detectors. The analyzer thus simultaneously samples multiple wavelengths in the reflected spectrum. From the resulting samples, a computer deconvolutes the spectral line shape into a measurement of the local electric field and the local carrier concentration. Author
- Solid State Physics
- Test Facilities, Equipment and Methods