System and method for deducing charge density gradients in doped semiconductors

Patent metadata

Field	Value
Publication number	US-10215796-B2
Application number	US-201615151216-A
Country	US
Kind code	B2
Filing date	May 10, 2016
Priority date	May 11, 2015
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

A system and a method determine a quality of a doped semiconductor layer in terms of a charge carrier density gradient by measuring two magnetic-field-dependent resistances using four contacts of a specimen.

First claim

We claim:

1. A system, comprising:
a measuring device including terminal contacts, the terminal contacts contacting a specimen of a semiconductor, where the measuring device applies a current and measures the voltage at the terminal contacts to determine a quality of the specimen in terms of a charge carrier density gradient by measuring two magnetic-field-dependent resistances using the terminal contacts.

2. The system of claim 1 , where the measuring device extracts either an angle or a magnitude of the charge carrier density gradient, or both the angle and the magnitude of the charge carrier density gradient.

3. The system of claim 2 , where the charge carrier density gradient reveals a density distribution of a surrounding area of the specimen, allowing estimates of neighboring densities to be accurately made.

4. The system of claim 1 , where the charge carrier density gradient reveals a density distribution of the surrounding area of the specimen, allowing estimates of neighboring densities to be accurately made.

5. The system of claim 1 , further comprising examining a few scattered specimen from a large area of the semiconductor to determine a uniformity of a density distribution over an entire semiconductor without testing every position.

6. The system of claim 1 , where an angle of the charge carrier density gradient

θ
=

tan

-
1

⁡

(

η
y

η
x

)

is determined by application of magnetic field.

7. The system of claim 1 , where a magnitude of the charge carrier density gradient |η|=√{square root over (η x 2 +η y 2 )} is determined by application of magnetic field.

8. The system of claim 1 , where the terminal contacts rotate the charge carrier density gradient angle by about 45 degrees to measure the charge carrier density gradient.

9. The system of claim 1 , where a number of terminal contacts comprises at least four.

10. The system of claim 9 , where only two magnetic-field-dependent resistances are measured using the at least four terminal contacts.

11. A method, comprising:
contacting a specimen at terminal contacts;
applying a current and measuring a voltage at the terminal contacts; and
measuring two magnetic-field-dependent resistances using the terminal contacts to determine a quality of the specimen in terms of a charge carrier density gradient.

12. The method of claim 11 , where the measuring extracts both an angle and a magnitude of the charge carrier density gradient.

13. The method of claim 12 , where the charge carrier density gradient reveals a density distribution of a surrounding area of the specimen, allowing estimates of neighboring densities to be accurately made.

14. The method of claim 11 , where the charge carrier density gradient reveals a density distribution of the surrounding area of the specimen, allowing estimates of neighboring densities to be accurately made.

15. The method of claim 11 , further comprising:
examining a few scattered specimen from a large area of the semiconductor; and
determining a uniformity of a density distribution over an entire semiconductor without testing every position.

16. The method of claim 11 , further comprising determining an angle of the charge carrier density gradient

θ
=

tan

-
1

⁡

(

η
y

η
x

)

by applying a magnetic field.

17. The method of claim 11 , determining a magnitude of the charge carrier density gradient |η|=√{square root over (η x 2 +η y 2 )} from applying a magnetic field.

18. The method of claim 11 , further comprising rotating the charge carrier density gradient angle by about 45 degrees to measure the charge carrier density gradient.

19. The method of claim 11 , where a number of terminal contacts comprises at least four.

20. The method of claim 19 , where only two magnetic-field-dependent resistances are measured using the at least four terminal contacts.

Assignees

• Univ Northwestern

Inventors

• Grayson Matthew
• Zhou Wang

Classifications

• G01R31/2648 Primary

  Characterising semiconductor materials (testing of materials or semi-finished products G01R31/2831; testing during manufacture H10P74/00) · CPC title