Nanostructure multilayer dielectric materials for capacitors and insulators

• US 5,742,471 A
• Filed: 11/25/1996
• Issued: 04/21/1998
• Est. Priority Date: 11/25/1996
• Status: Expired due to Term

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Johnson, Gary W., Barbee, Troy W. Jr.
• Primary Examiner(s): Kincaid, Kristine L.
• Assistant Examiner(s): Dinkins, Anthony
• Application Number:
  US08/755,619
• Time in Patent Office: 512 Days
• Field of Search: 361/301.4, 361/301.5, 361/306.3, 361/311-313, 361/320, 361/321.1-321.5, 361/322, 361/328, 361/326, 361/330, 257/528, 257/532, 29/25.42, 428/610, 428/660, 428/627, 428/632, 428/635, 428/698, 428/702
• US Class Current: 361/312
• CPC Class Codes: H01G 4/10 Metal-oxide dielectrics H01G4/085 takes precedence
• CPC Class Codes: H01G 4/20 using combinations of dielectrics from more than one of groups H01G4/02 - H01G4/06 H01G4/12 takes precedence
• CPC Class Codes: Y10T 29/435 Solid dielectric type

Abstract

A capacitor is formed of at least two metal conductors having a multilayer dielectric and opposite dielectric-conductor interface layers in between. The multilayer dielectric includes many alternating layers of amorphous zirconium oxide (ZrO₂) and alumina (Al₂ O₃). The dielectric-conductor interface layers are engineered for increased voltage breakdown and extended service life. The local interfacial work function is increased to reduce charge injection and thus increase breakdown voltage. Proper material choices can prevent electrochemical reactions and diffusion between the conductor and dielectric. Physical vapor deposition is used to deposit the zirconium oxide (ZrO₂) and alumina (Al₂ O₃) in alternating layers to form a nano-laminate.

Claims

1. A capacitor, comprising:

at least one pair of metal conductor layers that function as capacitor electrodes;

a dielectric-conductor interface layer in between and in contact with each of the conductor layers; and

a multilayer dielectric disposed between and in contact on opposite sides with corresponding dielectric-conductor interface layers and comprising a plurality of alternating layers of oxides of at least two different metals.

2. The capacitor of claim 1, wherein:

the multilayer dielectric includes zirconium oxide (ZrO₂) and alumina (Al₂ O₃) in alternating layers.

3. The capacitor of claim 1, wherein:

the dielectric-conductor interface layers are comprised of materials that increase the local interfacial work function, wherein charge injection is limited to provide for increased breakdown voltage.

4. The capacitor of claim 1, wherein:

the dielectric-conductor interface layers are comprised of materials that provide for a limiting of electrochemical reactions and diffusion between the metal conductor layers and the multilayer dielectric.

5. The capacitor of claim 1, wherein:

the multilayer dielectric includes metal oxides laid down in alternating layers by physical vapor deposition to form a nano-laminate.

6. An insulator, comprising:

at least one pair of metal electrodes that provide for mechanical support between;

a dielectric-conductor interface layer in between and in contact with each of the pair of metal electrodes; and

a multilayer dielectric disposed between and in contact on opposite sides with corresponding dielectric-conductor interface layers and comprising a plurality of alternating layers of oxides of at least two different metals.

7. The insulator of claim 6, wherein:

the multilayer dielectric includes zirconium oxide (ZrO₂) and alumina (Al₂ O₃) in alternating layers.

8. The insulator of claim 6, wherein:

the dielectric-conductor interface layers are comprised of materials that increase the local interfacial work function, wherein charge injection is limited to provide for increased breakdown voltage.

9. The insulator of claim 6, wherein:

the dielectric-conductor interface layers are comprised of materials that provide for a limiting of electrochemical reactions and diffusion between the metal electrodes and the multilayer dielectric.

10. The insulator of claim 6, wherein:

the multilayer dielectric includes metal oxides laid down in alternating layers by physical vapor deposition to form a nano-laminate.