Methods of forming integrated circuit capacitors having composite titanium oxide and tantalum pentoxide dielectric layers therein

• US 6,300,215 B1
• Filed: 10/14/1999
• Issued: 10/09/2001
• Est. Priority Date: 10/19/1998
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Shin, Dong-won
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): Keshavan, Belur V
• Application Number:
  US09/417,859
• Time in Patent Office: 726 Days
• Field of Search: 438/396, 438/399, 438/253, 438/239, 438/240, 257/310, 257/296, 257/303
• US Class Current: 438/396
• CPC Class Codes: H01L 21/02183 the material containing tantalum, e.g. Ta2O5
• CPC Class Codes: H01L 21/02186 the material containing titanium, e.g. TiO2
• CPC Class Codes: H01L 21/02326 into a nitride layer, e.g. changing SiN to SiON
• CPC Class Codes: H01L 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/31604 Deposition from a gas or vapour H01L21/31691, H01L21/31695 take precedence
• CPC Class Codes: H01L 21/31691 with perovskite structure
• CPC Class Codes: H01L 28/55 with a dielectric comprising a perovskite structure material
• CPC Class Codes: H10B 12/315 with the capacitor higher than a bit line

Abstract

Methods of forming integrated circuit capacitors (e.g., DRAM capacitors) include the steps of forming a first capacitor electrode (e.g., polysilicon electrode) on a substrate and then forming a titanium nitride layer on the first capacitor electrode. A tantalum pentoxide dielectric layer is then formed on an upper surface of the titanium nitride layer. A step is then performed to convert the underlying titanium nitride layer into a titanium oxide layer. A second capacitor electrode is then formed on the tantalum pentoxide layer. The step of converting the titanium nitride layer into a titanium oxide layer is preferably performed by annealing the tantalum pentoxide layer in an oxygen ambient in a range between about 700° C. and 900° C. This oxygen ambient provides free oxygen to fill vacancies within the tantalum oxide layer and also provides free oxygen which diffuses into the underlying titanium nitride layer.

Claims

1. A method of forming an integrated circuit device, comprising the steps of:

forming a first conductive layer on a substrate;

forming a nitride compound layer on the first conductive layer;

forming a dielectric layer on the nitride compound layer, opposite the first conductive layer;

converting the nitride compound layer into an oxygen compound layer.

2. The method of claim 1, wherein said step of forming a nitride compound layer comprises the steps of:

forming a titanium metal layer on the first conductive layer;

converting the titanium metal layer to titanium nitride layer by annealing the titanium metal layer in a nitrogen ambient.

3. The method of claim 1, wherein said converting step comprises annealing the dielectric layer in an oxygen ambient in a range between about 700°

C. and 900°

C. to convert either a portion or the whole of the nitride compound layer into the oxygen compound layer.

4. The method of claim 2, wherein the titanium nitride layer has a thickness in a range between about 10 A and 200 A.

5. The method of claim 3, wherein the first conductive layer further comprises the rest portion of the nitride compound layer not being converted.

6. The method of claim 1, wherein the nitride compound layer, the oxygen compound layer, and the dielectric layer comprise at least TiN, TiO₂, and Ta₂O₅, respectively.

7. The method of claim 1, wherein said step of forming a titanium nitride layer comprises depositing titanium nitride on the first conductive layer using a titanium chloride source gas.

8. The method of claim 1, wherein said step of forming a dielectric layer is preceded by the steps comprising:

removing a portion of the nitride compound layer to expose a portion of the first conductive layer; and

forming a slilconoxynitride layer on the exposed portion of the first conductive layer.

9. The method of claim 8, wherein said step of forming a silicon oxynitride layer comprising the steps:

annealing the exposed portion of the first conductive layer in a nitrogen ambient;

forming a tantalum pentoxide layer on the exposed portion of the first conductive layer;

annealing the tantalum pentoxide layer in a oxygen ambient.

10. The method of claim 3, wherein the rest portion of the nitride compound layer not being converted comprises at least silicon oxynitride layer out of silicon oxynitride layer and nitride compound layer.

11. The method of claim 10, wherein said step of forming a dielectric layer is preceded by the steps comprising:

removing a portion of the nitride compound layer to expose a portion of the conductive layer; and

forming a silicon oxynitride layer on the exposed portion of the first conductive layer.

12. A method of forming an integrated circuit capacitor, comprising the steps of:

forming a first capacitor electrode over a substrate;

forming a titanium nitride layer on the first capacitor electrode;

forming a tantalum pentoxide dielectric layer on the titanium nitride layer;

annealing the tantalum pentoxide dielectric layer in an oxygen ambient to convert the titanium nitride layer into the titanium oxide layer; and

forming a second capacitor electrode on the tantalum pentoxide layer, opposite the first capacitor electrode.

13. A method of forming an integrated circuit capacitor, comprising the steps of:

forming a first capacitor electrode over a substrate;

forming a titanium nitride layer on the first capacitor electrode;

removing a portion of titanium nitride layer to expose the first portion of the first capacitor electrode;

annealing the substrate in a nitrogen ambient;

forming a tantalum pentoxide dielectric layer on the remainder of the titanium nitride layer and the exposed first capacitor;

annealing the tantalum pentoxide dielectric layer in an oxygen ambient to convert titanium nitride layer into a titanium oxide layer and to form a silicon oxynitride layer on the exposed first capacitor electrode; and

forming a second capacitor electrode on the tantalum pentoxide layer.