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US5153503A
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Method and apparatus for measuring a carrier lifetime of iv group semiconductor
Assignee: Toshiba Corp
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Filing: 1991-03-26
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Granted: 1992-10-06
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Expires: 2011-03-26
Abstract
Abstract A method for measuring carrier lifetime of IV group semiconductors. The method includes the steps of irradiating pulse light, whose photon energy is larger than the bandgap of a IV group semiconductor and whose interval is sufficiently longer than the carrier lifetime of a IV group semiconductor, on a IV group semiconductor to be measured, exciting the IV group semiconductor, and generating excess carriers, obtaining a decay time of a band emission from a IV group semiconductor, and determining a carrier lifetime of the IV group semiconductor from the decay time of the band emission.
Inventors
- 👤 Akihiro Yahata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:43
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/63; G01N21/64; G01N21/6489
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
90 words
A method for measuring carrier lifetime of IV group semiconductor comprising the steps of: generating excess carriers in a IV group semiconductor to be measured, by irradiating pulse light, whose photon energy is larger than the bandgap of said IV group semiconductor and whose interval is sufficiently longer than the carrier lifetime of said IV group semiconductor; measuring a time that intensity of band emission of said IV group semiconductor reduces to 1/e of its initial intensity; and determining a carrier lifetime of said IV group semiconductor from said time.
Claim 2
Independent Claim
90 words
A method for measuring carrier lifetime of IV group semiconductor comprising the steps of: generating excess carriers in a IV group semiconductor to be measured, by irradiating pulse light, whose photon energy is larger than the bandgap of said IV group semiconductor and whose interval is sufficiently longer than the carrier lifetime of said IV group semiconductor; measuring a time that intensity of band emission of said IV group semiconductor reduces to 1/e of its initial intensity; and determining a carrier lifetime of said IV group semiconductor from said time.
Claim 3
Dependent Claim
31 words
The method according to claim 1, wherein said interval of said pulse light is 10 ms or more and the energy per one pulse ranges from 5 μJ to 5 mJ.
Claim 4
Dependent Claim
29 words
The method according to claim 1, wherein said pulse light is emitted from a dye laser excited by a nitrogen laser or second harmonics generation of a YAG laser.
Claim 5
Dependent Claim
34 words
The method according to claim 3, wherein the energy per one pulse of said nitrogen laser is such that the energy per one pulse said dye laser ranges from 5 μJ to 5 mJ.
Claim 6
Dependent Claim
25 words
The method according to claim 1, wherein said pulse light is emitted from a dye laser excited by second harmonics generation of a YAG laser.
Claim 7
Dependent Claim
40 words
The method according to claim 5, wherein said energy per one pulse from said second harmonics generation of said YAG laser is such that type energy per one pulse of said dye laser ranges from 5 μJ to 5 mJ.
Claim 8
Dependent Claim
44 words
The method according to claim 1, wherein said step for measuring a time that intensity of band emission of said IV group semiconductor reduces to 1/e of its initial intensity comprise the steps of: amplifying said band emission; and averaging said amplified band emission.
Claim 9
Dependent Claim
19 words
The method according to claim 1, wherein said step for determining said carrier lifetime is performed by using oscilloscope.
Claim 10
Independent Claim
94 words
An apparatus for measuring carrier lifetime of IV group semiconductor comprising: a light source for generating pulse light whose photon energy is larger than the bandgap of said IV group semiconductor and whose interval is longer then the carrier lifetime of said IV group semiconductor; introducing means for introducing said pulse light into said IV group semiconductor; detecting means for detecting band emission emitted from said IV group semiconductor excited by said pulse light; and evaluating means for evaluating the carrier life of said IV group semiconductor from the output of said detecting means.
Claim 11
Independent Claim
94 words
An apparatus for measuring carrier lifetime of IV group semiconductor comprising: a light source for generating pulse light whose photon energy is larger than the bandgap of said IV group semiconductor and whose interval is longer then the carrier lifetime of said IV group semiconductor; introducing means for introducing said pulse light into said IV group semiconductor; detecting means for detecting band emission emitted from said IV group semiconductor excited by said pulse light; and evaluating means for evaluating the carrier life of said IV group semiconductor from the output of said detecting means.
Claim 12
Dependent Claim
38 words
The apparatus according to claim 9, wherein said light source generates pulse light wherein said interval of said pulse light is 10 ms or more and the energy per one pulse ranges from 5 μJ to 5 mJ.
Claim 13
Dependent Claim
24 words
The apparatus according to claim 9, wherein said light source is composed of a dye laser and a nitrogen laser exciting the dye laser.
Claim 14
Dependent Claim
23 words
The apparatus according to claim 11, wherein the energy per one pulse of the dye laser ranges from 5 μm to 5 mJ.
Claim 15
Dependent Claim
28 words
The apparatus according to claim 9, wherein said light source is composed of a dye laser and second harmonic generation of a YAG laser exciting the dye laser.
Claim 16
Dependent Claim
21 words
The apparatus according to claim 13, wherein said dye laser is excited by a second harmonic generation of said YAG laser.
Claim 17
Dependent Claim
27 words
The apparatus according to claim 9, wherein said detecting means is composed of a photo-multiplier having good sensitivity for a infrared wavelength region (so-called S 1 type).
Claim 18
Dependent Claim
15 words
The apparatus according to claim 9, wherein said evaluating means is composed of an oscilloscope.
Claim 19
Dependent Claim
29 words
The apparatus according to claim 9, wherein the output of said detecting means is amplified by amplifying means and averaged by averaging means, and introduced into said evaluating means.
Claim 20
Dependent Claim
16 words
The apparatus according to claim 17, wherein said averaging means is composed of a boxcar averager.
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