Method and assembly for determining the carbon content in silicon

Patent metadata

Field	Value
Publication number	US-10317338-B2
Application number	US-201715716598-A
Country	US
Kind code	B2
Filing date	Sep 27, 2017
Priority date	Sep 27, 2016
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

A method of determining the carbon content in a silicon sample may include: generating electrically active polyatomic complexes within the silicon sample. Each polyatomic complex may include at least one carbon atom. The method may further include: determining a quantity indicative of the content of the generated polyatomic complexes in the silicon sample, and determining the carbon content in the silicon sample from the determined quantity.

First claim

What is claimed is:

1. A method of determining a carbon content in a silicon sample, the method comprising:
generating electrically active polyatomic complexes within the silicon sample, wherein each polyatomic complex comprises at least one carbon atom;
determining a quantity indicative of the content of the generated polyatomic complexes in the silicon sample; and
determining the carbon content in the silicon sample from the determined quantity.

2. The method of claim 1 ,
wherein at least one polyatomic complex, a plurality of polyatomic complexes, or most polyatomic complexes comprises/comprise at least one oxygen atom or a plurality of oxygen atoms.

3. The method of claim 1 ,
wherein the generating the polyatomic complexes comprises displacing carbon atoms from substitutional lattice sites to interstitial lattice sites,
wherein optionally the displacing is performed by particle irradiation of the silicon sample,
wherein further optionally the particles comprise protons and/or electrons and/or neutrons and/or alpha particles.

4. The method of claim 1 ,
wherein the generating the polyatomic complexes comprises annealing the silicon sample,
wherein optionally the annealing is performed at a temperature in a range from about 450° C. to about 520° C., further optionally at a temperature of about 490° C.

5. The method of claim 4 ,
wherein the annealing is performed over a period in a range from about 30 minutes to about 7 hours, optionally over a period in a range from about 1 hour to about 5 hours.

6. The method of claim 1 ,
wherein at least some of the polyatomic complexes comprise at least one hydrogen atom.

7. The method of claim 1 ,
wherein at least some of the polyatomic complexes are configured as shallow donors.

8. The method of claim 1 ,
wherein the determining the quantity indicative of the content of the polyatomic complexes in the silicon sample is performed by a spectroscopic method,
wherein optionally the spectroscopic method comprises Fourier Transform Infrared Spectroscopy (FTIR),
wherein further optionally the Fourier Transform Infrared Spectroscopy (FTIR) is performed at a temperature in a range from about 4 K to about 20 K, further optionally at a temperature of about 10 K.

9. The method of claim 8 ,
wherein during the determination of the quantity indicative of the content of the polyatomic complexes, the silicon sample is irradiated with visible light.

10. The method of claim 8 , further comprising:
identifying at least one characteristic peak in a spectrum obtained by the spectroscopic method.

11. The method of claim 10 ,
wherein the quantity indicative of the content of the polyatomic complexes in the silicon sample is determined as a height of the identified at least one characteristic peak and/or an integrated area of the identified at least one characteristic peak.

12. The method of claim 11 ,
wherein the spectroscopic method comprises the identification of a plurality of characteristic peaks and the quantity indicative of the content of the polyatomic complexes in the silicon sample is determined as a sum of the integrated areas of the plurality of characteristic peaks.

13. The method of claim 1 ,
wherein the determining the carbon content in the silicon sample is performed using a calibration curve assigning a unique carbon content to the determined quantity indicative of the content of the polyatomic complexes in the silicon sample.

14. The method of claim 13 ,
wherein the calibration curve is chosen depending on an oxygen content in the silicon sample to be analyzed,
wherein optionally the oxygen content in the silicon sample to be analyzed is determined by Fourier Transform Infrared Spectroscopy (FTIR),
wherein further optionally the oxygen content is determined by Fourier Transform Infrared Spectroscopy (FTIR) performed at room temperature.

15. The method of claim 1 ,
wherein the silicon sample is grown by the Czochralski method, optionally by the magnetic Czochralski method.

16. A measuring assembly for determining the carbon content in a silicon sample, wherein the assembly comprises:
a polyatomic-complex generation unit configured to generate electrically active polyatomic complexes within the silicon sample, wherein each polyatomic complex comprises at least one carbon atom;
a first determination unit configured to determine a quantity indicative of the content of the generated polyatomic complexes in the silicon sample; and
a second determination unit configured to determine the carbon content in the silicon sample from the determined quantity.

17. The measuring assembly of claim 16 ,
wherein at least one polyatomic complex, a plurality of polyatomic complexes, or most polyatomic complexes comprises/comprise at least one oxygen atom or a plurality of oxygen atoms.

18. The measuring assembly of claim 16 ,
wherein the polyatomic complex generation unit comprises an irradiation sub-unit configured to irradiate the silicon sample with particles, wherein optionally the particles comprise protons and/or electrons and/or neutrons and/or alpha particles.

19. The measuring assembly of claim 16 ,
wherein the polyatomic-complex generation unit comprises an annealing sub-unit configured to anneal the silicon sample.

20. The measuring assembly of claim 16 ,
wherein the first determination unit includes a spectrometer, optionally configured as an FTIR spectrometer.

21. The measuring assembly of claim 20 ,
wherein the spectrometer is operable at a temperature in a range from about 4 K to about 20 K.

22. The measuring assembly of claim 20 ,
wherein the first determination unit is configured to determine at least one characteristic peak in a spectrum acquired by means of the spectrometer.

23. The measuring assembly of claim 22 ,
wherein the first determination unit is configured to determine a height of the at least one characteristic peak and/or an area under the at least one characteristic peak as the quantity indicative of the content of the polyatomic complexes in the silicon sample.

24. The measuring assembly of claim 23 ,
wherein the first determination unit is configured to identify a plurality of characteristic peaks and to determine the quantity indicative of the content of the polyatomic complexes in the silicon sample as a sum of the areas under the plurality of characteristic peaks.

25. The measuring assembly of claim 16 ,
wherein the first determination unit is configured to irradiate the silicon sample with visible light during determining the quantity indicative of the content of the polyatomic complexes.

26. The measuring assembly of claim 16 ,
wherein the second determination unit is configured to determine the carbon content in the silicon sample using a calibration curve assigning a unique carbon content to the determined quantity indicative of the content of the polyatomic complexes in the silicon sample,
wherein optionally the second determination unit is configured to choose the calibration curve depending on an oxygen content in the silicon sample to be analyzed.

Assignees

• Infineon Technologies Ag

Inventors

• Ganagona Naveen Goud
• Jelinek Moriz
• Oefner Helmut
• Schulze Hans-Joachim
• Schustereder Werner

Classifications

• G01N2021/3572

  Preparation of samples, e.g. salt matrices · CPC title

• G01N2021/3595

  using FTIR · CPC title

• G01N2021/3568

  applied to semiconductors, e.g. Silicon · CPC title

• G01N21/3563 Primary

  for analysing solids; Preparation of samples therefor · CPC title