Method for measuring the electrical potential in a semiconductor element

• US 5,723,981 A
• Filed: 06/25/1996
• Issued: 03/03/1998
• Est. Priority Date: 08/29/1994
• Status: Expired due to Term

• Current Assignee: Imec Company
• Original Assignee: IMEC International
• Inventors: Vandervorst, Wilfried, Trenkler, Thomas, De Wolf, Peter, Hellemans, Louis C.
• Primary Examiner(s): Nguyen, Vinh P.
• Assistant Examiner(s): DO, DIEP N
• Application Number:
  US08/673,616
• Time in Patent Office: 616 Days
• Field of Search: 324/715, 324/717, 324/718, 324/719, 324/722, 324/724, 324/754, 324/756, 324/758, 324/762, 324/765, 73/105, 250/306, 250/307
• US Class Current: 324/719
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01Q 60/30 Scanning potential microscopy
• CPC Class Codes: H01L 22/14 for electrical parameters, e.g. resistance, deep-levels, CV, diffusions by electrical means
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/014 Solder alloys
• CPC Class Codes: Y10S 977/854 Semiconductor sample

Abstract

Measuring an electrical potential in a semiconductor element by applying one or more voltages over the semiconductor element, placing one or more conductors in contact with the semi-conductor element using a scanning proximity microscope, calibrating the contact force between the conductors and the semiconductor element and measuring an electrical potential in the semi-conductor element with at least one of the conductors while injecting a substantially zero current in the semiconductor element. To measure the electrical potential distribution within the semiconductor, the position of at least one of the conductors is changed and the electric potential re-measured.

Claims

1. A method of measuring an electrical potential distribution in a semiconductor element, comprising the steps of:

(a) applying a voltage over said semiconductor element;

(b) placing a conductor in contact with said semiconductor element in a region of said semiconductor element with a known electrical potential using a scanning proximity microscope while injecting a substantially zero current in said semiconductor element with said conductor;

(c) monitoring the electrical potential on said conductor;

(d) monitoring the contact force between said conductor and said semiconductor element;

(e) increasing contact force between said conductor and said semiconductor element until a first substantial change in said contact force is recorded and until a first substantial change in said electrical potential is recorded, the monitored electrical potential attaining thereby substantially the same value as said known electrical potential and the contact force corresponding to said first substantial change being a calibrated contact force;

thereafter

(f) changing the position of said conductor while applying said calibrated contact force on said conductor;

(g) measuring the electrical potential on said conductor while injecting a substantially zero current in said semiconductor element with said conductor; and

(h) repeating steps (f) and (g).

2. The method as recited in claim 1 adapted for measuring said electrical potential on a cross-section of said semiconductor element.

3. The method as recited in claim 2, wherein said cross-section is formed by cleaving said semi-conductor element.

4. The method as recited in claim 2, wherein said cross-section is formed by polishing said semi-conductor element.

5. The method as recited in claim 2 wherein said cross-section is formed by chemical etching said semi-conductor element.

6. The method as recited in claim 2, wherein said cross-section is formed by ion-beam milling said semi-conductor element.

7. The method as recited in claim 2, wherein said cross-section is formed by sawing said semi-conductor element.

8. The method as recited in claim 2 wherein said cross-section is formed by sputter-etching said semi-conductor element.

9. The method as recited in claim 2, wherein said cross-section is formed by bevel etching said semi-conductor element.

10. The method as recited in claim 1, further comprising the step of:

(i) oscillating said conductor in a direction substantially perpendicular to the surface of said semiconductor element during step (g).

11. The method as recited in claim 1, wherein said voltage is applied by applying a voltage between two or more contacts arranged on said semiconductor element.

12. The method as recited in claim 1, wherein said voltage is applied by placing said semiconductor element in a magnetic field.

13. The method as recited in claim 1, wherein said voltage is applied by placing said semiconductor element in an electromagnetic field.

14. The method is recited in claim 1, wherein said voltage is applied by subjecting said semiconductor element to electromagnetic radiation.

15. The method as recited in claim 1, wherein said scanning proximity microscope is an atomic force microscope.

16. The method as recited in claim 1, wherein said scanning proximity microscope is a scanning tunneling microscope.

17. The method as recited in claim 1, wherein said conductors is an electrically conducting, relatively hard probe.

18. The method as recited in claim 17, wherein said probe is selected from the group consisting of diamond, boron implanted diamond, tungsten coated diamond, diamond-like-carbon, silicon, diamond-coated silicon, silicide-coated silicon and nitride-coated silicon.

19. The method as recited in claim 1, adapted for measuring a characteristic of said semiconductor element, further comprising the steps of:

establishing a relation between said electrical potential and said characteristic;

mapping the electrical potential distribution in said semiconductor element; and

converting said potential distribution to said characteristic using said relation.

20. The method as recited in claim 19 wherein said characteristic is the charge carrier distribution in said semiconductor element.

21. The method as recited in claim 19 wherein said conductor is moving substantially perpendicular over a surface of said semiconductor element in which is situated a p-n junction.