Conductive exotic-nitride barrier layer for high-dielectric-constant material electrodes

• US 5,851,896 A
• Filed: 06/07/1995
• Issued: 12/22/1998
• Est. Priority Date: 08/01/1994
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Summerfelt, Scott R.
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): MULPURI, SAVITRI
• Application Number:
  US08/485,177
• Time in Patent Office: 1,294 Days
• Field of Search: 437/60, 437/52, 437/919, 437/947, 437/190, 437/192, 257/295, 257/306, 148/DIG. 14, 148/DIG. 16, 438/341, 438/240, 438/653, 438/330
• US Class Current: 438/396
• CPC Class Codes: H01L 21/28568 the conductive layers comprising transition metals H01L21/28518 takes precedence
• CPC Class Codes: H01L 28/75 comprising two or more layers, e.g. comprising a barrier layer and a metal layer

Abstract

A preferred embodiment of this invention comprises an oxidizable layer (e.g. TiN 50), a conductive exotic-nitride barrier layer (e.g. Ti--Al--N 34) overlying the oxidizable layer, an oxygen stable layer (e.g. platinum 36) overlying the exotic-nitride layer, and a high-dielectric-constant material layer (e.g. barium strontium titanate 38) overlying the oxygen stable layer. The exotic-nitride barrier layer substantially inhibits diffusion of oxygen to the oxidizable layer, thus minimizing deleterious oxidation of the oxidizable layer.

Claims

1. A method of forming a microelectronic structure, said method comprising:

(a) providing a semiconductor substrate having a conductive oxidizable layer;

(b) forming a conductive nitride layer on said conductive oxidizable layer, said conductive nitride selected from the group consisting of;

titanium aluminum nitride, Zr nitride, Hf nitride, Y nitride, Sc nitride, La nitride, other rare earth nitrides, N deficient Al nitride, doped Al nitride, Mg nitride, Ca nitride, Sr nitride, Ba nitride, and combinations thereof;

(c) forming an oxygen stable layer on said conductive nitride layer, wherein said conductive nitride layer and said conductive oxidizable layer have different compositions and are in direct contact with each other; and

(d) forming a layer of a high-dielectric-constant material on said oxygen stable layer, wherein the conductive nitride layer substantially inhibits diffusion of oxygen to the conductive oxidizable layer, whereby deleterious oxidation of the conductive oxidizable layer is minimized.

2. The method according to claim 1, said method further comprising exposing said structure to oxygen between said steps (c) and (d) to pre-oxidize a sidewall portion of said conductive nitride layer.

3. The method according to claim 1, said method further comprising exposing said structure to oxygen between said steps (c) and (d) to pre-oxidize an upper surface portion of said conductive nitride layer.

4. The method according to claim 1, wherein said conductive oxidizable layer is selected from the group consisting of:

tantalum, tungsten, titanium, molybdenum, titanium nitride, zirconium nitride, titanium silicide, tantalum silicide, tungsten silicide, molybdenum silicide, tantalum carbide, titanium boride, boron carbide, silicon, germanium, carbon, GaAs, and combinations thereof.

5. The method according to claim 1, wherein said high-dielectric-constant material is selected from the group consisting of:

barium strontium titanate, lead zirconate titanate, lead lanthanum titanate, lead lanthanum zirconate titanate, bismuth titanate, potassium tantalate, lead scandium tantalate, lead niobate, lead zinc niobate, potassium niobate, lead magnesium niobate, and combinations thereof.

6. The method according to claim 1, wherein said oxygen stable layer comprises platinum.

7. The method according to claim 1, wherein said oxygen stable layer is selected from the group consisting of:

platinum, palladium, rhenium, rhodium, ruthenium oxide, tin oxide, indium oxide, rhenium oxide, osmium oxide, rhodium oxide, iridium oxide, and combinations thereof.

8. The method according to claim 1, said method further comprising forming an upper electrode on said high-dielectric-constant material layer.

9. The method according to claim 8, wherein said upper electrode is selected from the group consisting of:

tungsten, tungsten nitride, titanium, titanium nitride, ruthenium dioxide, YBa₂ Cu₃ O_7-x, platinum, palladium, rhodium, gold, iridium, silver, and combinations thereof.

10. A method of forming a microelectronic structure, said method comprising:

(a) providing a semiconductor substrate having a conductive oxidizable layer;

(b) forming a conductive nitride layer on said conductive oxidizable layer, wherein said conductive nitride is an alloy of a first material and a second material, said first material selected from the group consisting of;

titanium aluminum nitride, Zr nitride, Hf nitride, Y nitride, Sc nitride, La nitride, other rare earth nitrides, N deficient Al nitride, doped Al nitride, Mg nitride, Ca nitride, Sr nitride, Ba nitride, and combinations thereof, wherein said second material is selected from the group consisting of;

TiN, GaN, Ni Nitride, Co Nitride, Ta Nitride, W nitride, and combinations thereof;

(c) forming an oxygen stable layer on said conductive nitride layer on said conductive oxidizable layer, wherein said conductive nitride layer and said conductive oxidizable layer have different compositions and are in direct contact with each other; and

(d) forming a layer of a high-dielectric-constant material on said oxygen stable layer, wherein the conductive nitride layer substantially inhibits diffusion of oxygen to the conductive oxidizable layer.