Electrical measurements on semiconductors using corona and microwave techniques

• US 7,521,946 B1
• Filed: 03/29/2006
• Issued: 04/21/2009
• Est. Priority Date: 04/06/2005
• Status: Expired due to Fees

• Current Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Original Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Inventors: Janik, Gary R.
• Primary Examiner(s): TANG, MINH NHUT
• Application Number:
  US11/277,934
• Time in Patent Office: 1,119 Days
• Field of Search: None
• US Class Current: 324/754.31
• CPC Class Codes: G01R 31/2621 for testing field effect transistors, i.e. FET's
• CPC Class Codes: G01R 31/311 of integrated circuits G01R31/31728 takes precedence

Abstract

A corona-microwave system can generate accurate capacitance-voltage (C-V) and resistance-voltage (R-V) curves, thereby allowing the accurate determination of gate film capacitance, sheet resistance of implanted regions, and mobility of a substrate under a gate. The corona-microwave system can combine a corona deposition system, a Kelvin probe, and a microwave probe. The corona deposition system can deposit a corona charge on a surface of the semiconductor. The Kelvin and microwave probes can be used to make first and second electrical measurements of a layer/region of the semiconductor. The steps of charge deposition and probe measurements can be repeated to generate a curve plotting the first and second electrical measurements. Because the first and second electrical measurements can be accurately made, the extracted information from the curve is also accurate.

Claims

1. A method for generating an accurate capacitance-voltage (C-V) curve for a semiconductor, the method comprising:

(a) depositing a corona charge on a test gate electrode structure formed on a gate film;

(b) using a Kelvin probe to measure a surface voltage of the gate film;

(c) using a microwave probe to measure a capacitance of the gate film;

(d) repeating steps (a), (b), and (c) to generate the C-V curve.

2. The method of claim 1, further including extracting gate dielectric parameters from the C-V curve.

3. The method of claim 1, wherein in step (c) the microwave probe is operated in its capacitive measurement mode by measuring a shift in resonant frequency of a microwave cavity as the microwave probe is pulled up from the gate film.

4. The method of claim 1, wherein the Kelvin and microwave probes are positioned within 100 nm of the test gate electrode structure.

5. The method of claim 1, wherein the test gate electrode structure has a geometry that approximately matches an end of the microwave probe and also keeps a total capacitance around 10e-15 F.

6. The method of claim 1, wherein an end of the microwave probe has a size of approximately 1 um×

8 um, with 8 um spacing between conductors.

7. The method of claim 6, wherein the test gate electrode structure has a size of approximately 50 nm×

8 um.

8. The method of claim 1, wherein a region covered by the corona charge is significantly larger than the test gate electrode structure.

9. The method of claim 8, wherein the region covered by the corona charge has a size of approximately 70 um×

70 um and the test gate electrode structure has a size of approximately 50 nm×

8 um.

10. A method for extracting accurate parameters for a semiconductor, the method comprising:

(a) depositing a corona charge on a surface of the semiconductor;

(b) using a Kelvin probe to measure a first electrical characteristic of a layer of the semiconductor;

(c) using a microwave probe to measure a second electrical characteristic of the layer;

(d) repeating steps (a), (b), and (c) to generate a curve plotting the first and second electrical characteristics; and

(e) extracting the accurate parameters from the curve.