IP Library Granted Patent US 8,629,411
Granted Patent B2
US 8,629,411 · App. 13/181,724 · Granted Jan 14, 2014

Photoluminescence spectroscopy

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Quick Facts
Patent No.
US 8,629,411
App. No.
13/181,724
Granted
Jan 14, 2014
Kind
B2
Abstract

This invention relates to temperature-corrected photoluminescence spectroscopy which may be applied to semiconductors and, in particular, photovoltaic films.

Claims (47)

1. An in-line apparatus for measuring photoluminescence from a material on a substrate in a manufacturing process, comprising:

a light source configured to direct light along a light path through a lens onto a material deposited on a substrate positioned in a process chamber;

a spectrometer configured to receive light emitted from the material and generate photoluminescence data for the material; and

a temperature measurement device configured to measure the temperature of the material.

2. The apparatus of claim 1 , wherein the light source comprises a laser.

3. The apparatus of claim 2 , wherein the laser has a power ranging from about 0 mW to about 400 mW.

4. The apparatus of claim 3 , wherein the laser has a power ranging from about 30 mW to about 100 mW.

5. The apparatus of claim 1 , wherein the lens is configured to focus the light onto the material with a spot size of less than about 3 mm 2 .

6. The apparatus of claim 1 , wherein the lens is configured to focus the light onto the material with a spot size of about 1 mm 2 .

7. The apparatus of claim 1 , wherein the temperature measurement device comprises an infrared pyrometer.

8. The apparatus of claim 1 , further comprising a first optical fiber to direct light from the light source.

9. The apparatus of claim 8 , further comprising a second optical fiber to transmit the light emitted from the material.

10. The apparatus of claim 1 , further comprising a computer configured to receive a high-temperature photoluminescence data set from the spectrometer and a measured temperature from the temperature measurement device.

11. The apparatus of claim 10 , wherein the computer comprises:

a low-temperature photoluminescence data set; and a temperature correction equation describing the relation of photoluminescence to temperature for the material.

12. The apparatus of claim 11 , wherein the computer reads the measured temperature and applies the temperature correction equation to the high-temperature photoluminescence data set to produce a temperature-corrected photoluminescence data set.

13. The apparatus of claim 12 , wherein the computer compares the temperature-corrected photoluminescence data set to the low-temperature photoluminescence data set.

14. The apparatus of claim 12 , wherein the computer identifies material properties of the material based upon the temperature-corrected photoluminescence data set.

15. The apparatus of claim 14 , wherein the material properties include bandgap.

16. The apparatus of claim 14 , wherein the material properties include defect density.

17. The apparatus of claim 16 , wherein the module manufacture temperature range is between 25 degrees C. and 300 degrees C.

18. The apparatus of claim 14 , wherein the material properties include recombination mechanisms.

19. The apparatus of claim 1 , further comprising at least one additional lens through which the light passes and is converted between a focused light beam and a collimated light beam.

20. A system for measuring photoluminescence from a material on a substrate in a manufacturing process, comprising:

a substrate process chamber;

a light source configured to direct light along a light path through a first lens toward a substrate position in the process chamber;

a spectrometer configured to receive light emitted from the material and generate photoluminescence data for the material;

a temperature measurement device configured to measure the temperature of the material; and

at least one additional measurement device configured to measure a characteristic of the process chamber environment.

21. The system of claim 20 , further comprising a substrate positioned at the substrate position in the process chamber.

22. The system of claim 21 , wherein the substrate comprises a material deposited on the surface of the substrate.

23. The system of claim 22 , wherein the material comprises a semiconductor material.

24. The system of claim 23 , wherein the semiconductor material comprises copper indium gallium (di)selenide.

25. The system of claim 23 , wherein the semiconductor material comprises cadmium telluride.

26. The system of claim 20 , further comprising a second lens positioned proximate to the first lens to form an apparatus head configured to convert focused light to collimated light.

27. The system of claim 26 , wherein the apparatus head is configured to convert collimated light to focused light.

28. The system of claim 26 , wherein the apparatus head is positioned in the process chamber.

29. The system of claim 26 , wherein the apparatus head is positioned outside the process chamber and the process chamber comprises a window to allow light from the light source to be directed into the process chamber.

30. The system of claim 26 , further comprising a first optical fiber to direct light from the light source to the apparatus head.

31. The system of claim 30 , further comprising a second optical fiber to transmit light from the apparatus head to the spectrometer.

32. The system of claim 20 , wherein the at least one additional measurement device comprises a water vapor measurement device configured to measure the water vapor concentration inside the process chamber.

33. The system of claim 20 , wherein the at least one additional measurement device comprises an oxygen measurement device configured to measure the oxygen concentration inside the process chamber.

34. The system of claim 33 , further comprising a computer configured to correct photoluminescence data obtained from the material, wherein the correction is based on one or more of material temperature, oxygen concentration inside the process chamber, or water concentration inside the process chamber.

35. The system of claim 20 , further comprising a conveyor configured to position the substrate at the substrate position in the process chamber.

36. The system of claim 20 , wherein the substrate has a temperature of between about 25 degrees C. and about 400 degrees C.

37. The system of claim 20 , wherein the substrate has a temperature of between about 25 degrees C. and about 300 degrees C.

38. The system of claim 20 , wherein the substrate has a temperature of between about 25 degrees C. and about 200 degrees C.

Assignments (7)
RELEASE OF SECURITY INTEREST Recorded Feb 13, 2026
From: JPMORGAN CHASE BANK, N.A.
To: FIRST SOLAR, INC.
Reel/Frame 074858/0364 →
SECURITY INTEREST Recorded Jul 10, 2023
From: FIRST SOLAR, INC.
To: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 064237/0462 →
TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENT RIGHTS Recorded Nov 15, 2021
From: JPMORGAN CHASE BANK, N.A.
To: FIRST SOLAR, INC.
Reel/Frame 058132/0566 →
TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENT RIGHTS Recorded Nov 15, 2021
From: JPMORGAN CHASE BANK, N.A.
To: FIRST SOLAR, INC.
Reel/Frame 058132/0261 →
PATENT SECURITY AGREEMENT Recorded Jul 12, 2017
From: FIRST SOLAR, INC.
To: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 043177/0581 →
CORRECTIVE ASSIGNMENT TO CORRECT THE PATENT APPLICATION 13/895113 ERRONEOUSLY ASSIGNED BY FIRST SOLAR, INC. TO JPMORGAN CHASE BANK, N.A. ON JULY 19, 2013 PREVIOUSLY RECORDED ON REEL 030832 FRAME 0088. ASSIGNOR(S) HEREBY CONFIRMS THE CORRECT PATENT APPLICATION TO BE ASSIGNED IS 13/633664. Recorded Sep 19, 2014
From: FIRST SOLAR, INC.
To: JPMORGAN CHASE BANK, N.A.
Reel/Frame 033779/0081 →
SECURITY AGREEMENT Recorded Jul 19, 2013
From: FIRST SOLAR, INC.
To: JPMORGAN CHASE BANK, N.A.
Reel/Frame 030832/0088 →