Method of making a thin film capacitor with an improved top electrode

• US 6,380,580 B1
• Filed: 08/10/2001
• Issued: 04/30/2002
• Est. Priority Date: 02/25/1998
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Arita, Koji
• Primary Examiner(s): Flynn, Nathan
• Assistant Examiner(s): QUINTO, KEVIN V
• Application Number:
  US09/925,705
• Publication Number:
  US 20020030218A1
• Time in Patent Office: 263 Days
• Field of Search: 257/295, 257/296, 257/306, 257/310, 257/303, 257/307, 257/532
• US Class Current: 257/310
• CPC Class Codes: H01L 28/55 with a dielectric comprising a perovskite structure material
• CPC Class Codes: H01L 28/75 comprising two or more layers, e.g. comprising a barrier layer and a metal layer

Abstract

A method of making a top electrode for a thin film capacitor with a multi-layer structure that includes a high dielectric oxide layer, a first conductive layer on the high dielectric oxide layer and having a high formability to a reactive ion etching, and a second conductive layer on the first conductive layer, the second conductive layer having a high formability to the reactive ion etching. The first conductive layer is deposited with a lower deposition rate than the second conductive layer wherein an interface between the first conductive layer and the high dielectric oxide layer is such that a density of a leak current across the interface is suppressed at not higher than 1×10⁻⁸ A/cm² upon applying a voltage of 2V across the dielectric oxide layer after the multi-layer structure has been subjected to a heat treatment at 350° C.

Claims

1. A multi-layer structure comprising:

a high dielectric oxide layer;

a first conductive layer on said high dielectric oxide layer, and said first conductive layer processing a high formability to a reactive ion etching; and

a second conductive layer on said first conductive layer, and said second conductive layer processing a high formability to said reactive ion etching,

wherein an interface between said first conductive layer and said high dielectric oxide layer is such that a density of a leak current across said interface is suppressed at not higher than 1×

10<sup>−

8</sup> A/cm² upon applying a voltage of 2V across said dielectric oxide layer after said multi-layer structure has been subjected to a heat treatment at 350°

C.

2. The multi-layer structure as claimed in claim 1, wherein said first conductive layer and said second conductive layer are made of the same conductive material which includes at least any one selected from the group consisting of Ru, RuO₂, Ir, IrO₂, and alloys thereof.

3. The multi-layer structure as claimed in claim 1, wherein said first conductive layer and said second conductive layer are made of different conductive materials, each of which includes at least any one selected from the group consisting of Ru, RUO₂, Ir, IrO₂, and alloys thereof.

4. The multi-layer structure as claimed in claim 3, wherein said first conductive layer consists essentially of Ru and said second conductive layer consists essentially of Ir.

5. The multi-layer structure as claimed in claim 1, wherein said first conductive layer has a thickness of about one-tenth of a thickness of said second conductive layer.

6. A top electrode structure of a thin film capacitor, said structure comprising:

a first conductive layer on a high dielectric oxide layer, and said first conductive layer processing a high formability to a reactive ion etching; and

a second conductive layer on said first conductive layer, and said second conductive layer processing a high formability to said reactive ion etching,

wherein an interface between said first conductive layer and said high dielectric oxide layer is such that a density of a leak current across said interface is suppressed at not higher than 1×

10<sup>−

8</sup> A/cm² upon applying a voltage of 2V across said dielectric oxide layer after said multi-layer structure has been subjected to a heat treatment at 350°

C.

7. The top electrode structure as claimed in claim 6, wherein said first conductive layer and said second conductive layer are made of the same conductive material which includes at least any one selected from the group consisting of Ru, RuO₂, Ir, IrO₂, and alloys thereof.

8. The top electrode structure as claimed in claim 6, wherein said first conductive layer and said second conductive layer are made of different conductive materials, each of which includes at least any one selected from the group consisting of Ru, RuO₂, Ir, IrO₂, and alloys thereof.

9. The top electrode structure as claimed in claim 8, wherein said first conductive layer consists essentially of Ru and said second conductive layer consists essentially of Ir.

10. The top electrode structure as claimed in claim 6, wherein said first conductive layer has a thickness of about one-tenth of a thickness of said second conductive layer.