Non-contact resistivity measurement apparatus and method using femtosecond laser pulses to create an electron flow

• US 5,563,508 A
• Filed: 03/31/1995
• Issued: 10/08/1996
• Est. Priority Date: 03/31/1995
• Status: Expired due to Fees

• Current Assignee: Panasonic Technologies, Inc. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Technologies, Inc. (Panasonic Holdings Corporation)
• Inventors: Tatah, Abdelkrim
• Primary Examiner(s): Nguyen, Vinh P.
• Application Number:
  US08/414,539
• Time in Patent Office: 557 Days
• Field of Search: 324/71.5, 324/73.1, 324/158.1, 324/765, 324/750, 324/752, 324/751, 324/72.5, 324/719, 324/722, 356/237, 356/400, 356/401, 364/550
• US Class Current: 324/702
• CPC Class Codes: G01R 27/00 Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
• CPC Class Codes: G01R 31/2656 using non-ionising electromagnetic radiation, e.g. optical radiation

Abstract

Apparatus and method for measuring the resistivity of a material without contacting or damaging the material, using a current and voltage meter connected to a first probe and a second probe. The probes are placed adjacent the material and in spaced relation to the material, a first ultraviolet laser beam having femtosecond pulses is focused onto the first probe such that the first probe emits electrons toward the material, and a second ultraviolet laser beam having femtosecond pulses is focused onto the material such that the material emits electrons toward the second probe. A voltage and a closed current loop are thus created. The current and voltage meter measures the current and voltage to obtain current and voltage readings, and the current and voltage readings are used to determine the resistivity of the material.

Claims

1. A method for measuring the resistivity of a material without contacting or damaging the material, using means for measuring current and voltage connected to a first probe and a second probe, comprising the steps of:

(a) disposing said first probe adjacent said material and in spaced relation thereto;

(b) disposing said second probe adjacent said material and in spaced relation thereto;

(c) focusing a first ultraviolet laser beam having short optical pulses onto said first probe such that said first probe emits electrons toward said material; and

(d) focusing a second ultraviolet laser beam having short optical pulses onto said material such that said material emits electrons toward said second probe, thereby creating a voltage across said first probe and said second probe and creating a closed current loop wherein current flows from said second probe, through said material, through said first probe, and through said means for measuring current and voltage.

2. A method as claimed in claim 1 further comprising the stems of measuring said current and said voltage using said means for measuring current and voltage to obtain current and voltage readings, and using said current and voltage readings to determine the resistivity of the material.

3. A method as claimed in claim 1 wherein said means for measuring current and voltage is a multimeter.

4. A method as claimed in claim 1 wherein said means for measuring current and voltage is an oscilloscope.

5. Apparatus for measuring the resistivity of a material without contacting or damaging the material, comprising:

(a) a first probe member disposed adjacent said material and in spaced relation thereto;

(b) a second probe member disposed adjacent said material and in spaced relation thereto;

(c) means for emitting electrons from said first probe member toward said material; and

(d) means for emitting electrons from said material toward said second probe member;

wherein voltage and closed current loop are generated, said current loop having current flowing from said second probe member, through said material, through said first probe member, and through a connection between said first probe member and said second probe member.

6. Apparatus as claimed in claim 5 further comprising means for measuring said voltage and said current to obtain voltage and current readings, wherein said voltage and current readings determine said resistivity.

7. Apparatus as claimed in claim 5 wherein said means for measuring said voltage and said current is a multimeter.

8. Apparatus as claimed in claim 5 wherein said means for measuring said voltage and said current is an oscilloscope.