Method and apparatus for determining minority carrier diffusion length in semiconductors
Abstract
Method and apparatus are provided for determining the diffusion length of minority carriers in semiconductor material, particularly amorphous silicon which has a significantly small minority carrier diffusion length using the constantmagnitude surfacephotovoltage (SPV) method. An unmodulated illumination provides the light excitation on the surface of the material to generate the SPV. A manually controlled or automatic servo system maintains a constant predetermined value of the SPV. A vibrating Kelvin methodtype probe electrode couples the SPV to a measurement system. The operating optical wavelength of an adjustable monochromator to compensate for the wavelength dependent sensitivity of a photodetector is selected to measure the illumination intensity (photon flux) on the silicon. Measurements of the relative photon flux for a plurality of wavelengths are plotted against the reciprocal of the optical absorption coefficient of the material. A linear plot of the data points is extrapolated to zero intensity. The negative intercept value on the reciprocal optical coefficient axis of the extrapolated linear plot is the diffusion length of the minority carriers.
 Inventors:

 (Princeton, NJ)
 (Mercerville, NJ)
 Issue Date:
 OSTI Identifier:
 864622
 Patent Number(s):
 4393348
 Application Number:
 06/228,575
 Assignee:
 RCA Corporation (New York, NY) OSTI
 DOE Contract Number:
 XJ982541
 Resource Type:
 Patent
 Country of Publication:
 United States
 Language:
 English
 Subject:
 method; apparatus; determining; minority; carrier; diffusion; length; semiconductors; provided; carriers; semiconductor; material; particularly; amorphous; silicon; significantly; constantmagnitude; surfacephotovoltage; spv; unmodulated; illumination; provides; light; excitation; surface; generate; manually; controlled; automatic; servo; maintains; constant; predetermined; value; vibrating; kelvin; methodtype; probe; electrode; couples; measurement; operating; optical; wavelength; adjustable; monochromator; compensate; dependent; sensitivity; photodetector; selected; measure; intensity; photon; flux; measurements; relative; plurality; wavelengths; plotted; reciprocal; absorption; coefficient; linear; plot; data; extrapolated; zero; negative; intercept; axis; carrier diffusion; optical wavelength; optical absorption; diffusion length; amorphous silicon; semiconductor material; minority carrier; predetermined value; absorption coefficient; photon flux; minority carriers; automatic servo; manually controlled; particularly amorphous; optical wave; modulated illumination; determining minority; constant predetermined; light excitation; wavelength dependent; reciprocal optical; magnitude surfacephotovoltage; /324/136/
Citation Formats
Goldstein, Bernard, Dresner, Joseph, and Szostak, Daniel J. Method and apparatus for determining minority carrier diffusion length in semiconductors. United States: N. p., 1983.
Web.
Goldstein, Bernard, Dresner, Joseph, & Szostak, Daniel J. Method and apparatus for determining minority carrier diffusion length in semiconductors. United States.
Goldstein, Bernard, Dresner, Joseph, and Szostak, Daniel J. Tue .
"Method and apparatus for determining minority carrier diffusion length in semiconductors". United States. https://www.osti.gov/servlets/purl/864622.
@article{osti_864622,
title = {Method and apparatus for determining minority carrier diffusion length in semiconductors},
author = {Goldstein, Bernard and Dresner, Joseph and Szostak, Daniel J.},
abstractNote = {Method and apparatus are provided for determining the diffusion length of minority carriers in semiconductor material, particularly amorphous silicon which has a significantly small minority carrier diffusion length using the constantmagnitude surfacephotovoltage (SPV) method. An unmodulated illumination provides the light excitation on the surface of the material to generate the SPV. A manually controlled or automatic servo system maintains a constant predetermined value of the SPV. A vibrating Kelvin methodtype probe electrode couples the SPV to a measurement system. The operating optical wavelength of an adjustable monochromator to compensate for the wavelength dependent sensitivity of a photodetector is selected to measure the illumination intensity (photon flux) on the silicon. Measurements of the relative photon flux for a plurality of wavelengths are plotted against the reciprocal of the optical absorption coefficient of the material. A linear plot of the data points is extrapolated to zero intensity. The negative intercept value on the reciprocal optical coefficient axis of the extrapolated linear plot is the diffusion length of the minority carriers.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1983},
month = {7}
}