Ferroelectric non-volatile variable resistive element

• US 5,070,385 A
• Filed: 10/20/1989
• Issued: 12/03/1991
• Est. Priority Date: 10/20/1989
• Status: Expired due to Term

• Current Assignee: Radiant Technologies A Partnership of New Mexico
• Original Assignee: Radiant Technologies, Inc. (Salesforce.com, Inc.)
• Inventors: Evans, Joseph T. Jr., Bullington, Jeff A.
• Primary Examiner(s): Jackson, Jr., Jerome
• Application Number:
  US07/424,809
• Time in Patent Office: 774 Days
• Field of Search: 357/51, 357/23.5, 357/23.15, 365/145, 365/117
• US Class Current: 257/537
• CPC Class Codes: G11C 11/22 using ferroelectric elements

Abstract

An improved non-volatile variable resistance element is disclosed. The resistive element is based on a semiconductor having a resistivity which is determined by the state of polarization of a ferroelectric layer.

Claims

1. A resistive element comprising:

a polarizable layer having first and second surfaces comprising a first material;

a first contact bonded to said polarizable layer adjacent to said first surface, said first contact being an electrical conductor; and

a second contact bonded to said polarizable layer adjacent to said second surface, said second contact comprising a semiconducting material which is doped such that the resistance of said second contact changes in response to a change in the polarization of said polarizable layer, said second contact further comprising first and second electrical connections disposed on said second contact such that the resistance of said second contact can be determined by connecting an electrical circuit between said first and second electrical connections, wherein first material and said semiconducting material are chosen such that ions drifting between said polarizable layer and said second contact do not give rise to a layer between said polarizable layer and said second contact having a dielectric constant substantially less than that of said first material.

2. The resistive element of claim 1 wherein said first material comprises a lead zirconate titanate and said semiconducting material comprises an oxide, bromide, carbide, nitride, or sulfide of an element.

3. The resistive element of claim 2 wherein said element is chosen from the group comprising tin, indium, beryllium, zinc, cadmium, and nickel.

4. The resistive element of claim 1 wherein said first material comprises a lead lanthium zirconate titanate and said semiconducting material comprises an oxide, bromide, carbide, nitride, or sulfide of an element.

5. The resistive element of claim 2 wherein said element is chosen from the group comprising tin, indium, beryllium, zinc, cadmium, and nickel.

6. The resistive element of claim 1 wherein said first contact comprises a semiconductor.

7. A resistive element comprising:

a polarizable layer having first and second surfaces comprising a first material;

a first contact bonded to said polarizable layer adjacent to said first surface, said first contact comprising a semiconducting material which is doped such that the resistance of said first contact changes in response to a change in the polarization of said polarizable layer; and

a second contact bonded to said polarizable layer adjacent to said second surface, said second contact comprising a semiconducting material which is doped such that the resistance of said second contact changes in response to a change in the polarization of said polarizable layer, said second contact further comprising first and second electrical connections disposed on said second contact such that the resistance of said second contact can be determined by connecting an electrical circuit between said first and second electrical connections

wherein first material and said semiconducting material are chosen such that ions drifting between said polarizable layer and said second contact do not give rise to a layer between said polarizable layer and said second contact having a dielectric constant simultaneously less than that of said first material.