Accession Number : ADD017298

Title :   Micro Photoreflectance Semiconductor Wafer Analyzer.

Descriptive Note : Patent, Filed 21 Dec 90, patented 15 Nov 94,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Bottka, Nicholas

Report Date : 15 Nov 1994

Pagination or Media Count : 10

Abstract : 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 sample's 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 sample's 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. (jg)

Descriptors :   *SEMICONDUCTORS, *LASERS, *REFLECTANCE, *WAFERS, *ANALYZERS, *PATENTS, *PHOTOELECTRIC EFFECT, FIBER OPTICS, FREQUENCY, SOURCES, MEASUREMENT, OPTICAL PROPERTIES, DETECTORS, SHAPE, LIGHT, CHARGE CARRIERS, ENERGY GAPS, HOLES(ELECTRON DEFICIENCIES), ELECTRIC FIELDS, ELECTRONS, SPECTRA, BROADBAND, SAMPLING, LINEAR ARRAYS, REFLECTIVITY, ENERGY BANDS, DISPERSIONS, SPECTRAL LINES, LINE SPECTRA

Subject Categories : Electrical and Electronic Equipment
      Physical Chemistry
      Electricity and Magnetism
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE