Method and apparatus for increasing bulk conductivity of a ferroelectric material

• US 6,932,957 B2
• Filed: 06/28/2002
• Issued: 08/23/2005
• Est. Priority Date: 06/28/2002
• Status: Active Grant

• Current Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Original Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Inventors: Risk, Gabriel C., Miller, Gregory D., Miles, Ronald O., McRae, Joseph M., Foulon, Gisele L., Galambos, Ludwig L., Alexandrovski, Alexei L., Caudillo, David, Lazar, Janos J.
• Primary Examiner(s): BOS, STEVEN J
• Application Number:
  US10/187,330
• Publication Number:
  US 20040163596A1
• Time in Patent Office: 1,152 Days
• Field of Search: 423/594.8, 252/584, 117/3
• US Class Current: 423/594.8
• CPC Class Codes: C01G 33/00 Compounds of niobium
• CPC Class Codes: C01G 35/00 Compounds of tantalum
• CPC Class Codes: C01P 2006/42 Magnetic properties
• CPC Class Codes: H03H 9/02559 of lithium niobate or lithium-tantalate substrates
• CPC Class Codes: H03H 9/02921 Measures for preventing electric discharge due to pyroelectricity

Abstract

In one embodiment, a ferroelectric material is processed by placing the material in an environment including metal vapor and heating the material to a temperature below the Curie temperature of the material. This allows the bulk conductivity of the ferroelectric material to be increased without substantially degrading its ferroelectric domain properties. In one embodiment, the ferroelectric material comprises lithium tantalate and the metal vapor comprises zinc.

Claims

1. A method of processing lithium tantalate, the method comprising:

placing the lithium tantalate in an environment including zinc vapor; and

heating the lithium tantalate to a temperature below a Curie temperature of the lithium tantalate.

2. The method of claim 1 wherein the temperature is less than or equal to about 595°

C.

3. The method of claim 1 further comprising:

after heating the lithium tantalate, creating a thermal gradient such that the zinc vapor precipitates at a location away from the lithium tantalate.

4. The method of claim 1 wherein the lithium tantalate is heated inside a sealed container with the zinc vapor.

5. The method of claim 4 wherein the sealed container contains an inert gas.

6. The method of claim 5 wherein the inert gas comprises argon.

7. The method of claim 4 wherein the sealed container contains a forming gas.

8. The method of claim 4 wherein the sealed container is heated in a process tube.

9. The method of claim 4 further comprising:

after heating the lithium tantalate, cooling the sealed container such that a first end of the sealed container is cooler than a second end of the sealed container to facilitate precipitation of the zinc vapor near the first end.

10. A method of processing a lithium tantalate material, the method comprising:

heating a lithium tantalate material at a temperature below the Curie temperature of the lithium tantalate material and in an environment including zinc vapor.

11. The method of claim 10 wherein the lithium tantalate material is heated inside a sealed container.

12. The method of claim 10 wherein the environment includes a forming gas.