Method for fabricating ferroelectric capacitor with improved interface surface characteristic

• US 6,238,934 B1
• Filed: 12/20/1999
• Issued: 05/29/2001
• Est. Priority Date: 12/30/1998
• Status: Expired due to Term

• Current Assignee: Hyundai Electronics Industries Co. Ltd. (SK Hynix Inc.)
• Original Assignee: Hyundai Electronics Industries Co. Ltd. (SK Hynix Inc.)
• Inventors: Yang, Woo-Seok
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): Thompson, Craig
• Application Number:
  US09/467,755
• Time in Patent Office: 526 Days
• Field of Search: 438/240, 438/3, 438/396, 148/DIG. 3
• US Class Current: 438/3
• CPC Class Codes: H10B 53/00 Ferroelectric RAM [FeRAM] devices comprising ferroelectric memory capacitors
• CPC Class Codes: H10B 53/30 characterised by the memory core region
• CPC Class Codes: Y10S 148/003 Anneal

Abstract

A method for fabricating a ferroelectric capacitor in a ferroelectric memory device includes the steps of forming a first conductive layer on a semiconductor structure prepared for a formation of ferroelectric capacitor, forming a first ferroelectric layer on said first conductive layer, carrying out a rapid thermal annealing for nucleation in said ferroelectric layer, forming a second conductive layer on said ferroelectric layer, and carrying out a thermal treatment for a grain growth in said ferroelectric layer, thereby the interface characteristics are improved, reducing leakage currents and preventing a peeling phenomenon during a following etching process.

Claims

1. A method for fabricating a ferroelectric capacitor in ferroelectric memory device, comprising the steps of:

a) forming a first conductive layer on a semiconductor structure prepared for a formation of the ferroelectric capacitor;

b) forming a ferroelectric layer on said first conductive layer;

c) carrying out a rapid thermal annealing for nucleation in said ferroelectric layer;

d) forming a second conductive layer on said ferroelectric layer; and

e) carrying out a thermal treatment for a grain growth in said ferroelectric layer.

2. The method as recited in claim 1, wherein said ferroelectric layer includes Sr_xBi_yTa₂O₉ and Sr_xBi_y(Ti_iNb_j)₂O₉, where x is 0.7 to 1.0, y is 2.0 to 2.6, i is 0.7 to 0.9, and j is 0.1 to 0.3.

3. The method as recited in claim 1, wherein the step c) is carried out at a temperature of 700°

C. to 800°

C. under an O₂ atmosphere for 0.4 to 0.6 minutes.

4. The method as recited in claim 2, wherein the step e) is carried out at a temperature of 700°

C. to 800°

C. under an O₂ atmosphere for 25 to 35 minutes.

5. A method for fabricating a ferroelectric capacitor in a ferroelectric memory device, comprising the steps of:

a) forming a first conductive layer on a semiconductor structure prepared for a formation of a ferroelectric capacitor;

b) forming a ferroelectric layer having a Bi-layered perovskite structure on said first conductive layer;

c) carrying out a rapid thermal annealing for nucleation in said ferroelectric layer;

d) forming a second conductive layer on said ferroelectric;

e) selectively etching said second conductive layer, said ferroelectric layer and said first conductive layer to form said ferroelectric capacitor;

f) carrying out a thermal treatment for compensating damages caused during an etching process and for promoting a grain growth in said ferroelectric layer;

g) forming an interlayer insulating layer, making planarization flow of said interlayer insulating layer, and carrying out a thermal treatment for a grain growth in said ferroelectric layer; and

h) etching said interlayer insulating layer to expose said second conductive layer, and carrying out a thermal treatment to compensate damages occurred during an etching of said interlayer insulating layer and to promote a grain growth in said ferroelectric layer.

6. The method as recited in claim 5, wherein said ferroelectric layer includes Sr_xBi_yTa₂O₉ and Sr_xBi_y(Ti_iNb_j)₂O₉, where x is 0.7 to 1.0, y is 2.0 to 2.6, i is 0.7 to 0.9, and j is 0.1 to 0.3.

7. The method as recited in claim 6, wherein the step c) is carried out at a temperature of 700 to 800°

C. in an O₂ atmosphere for 0.4 to 0.6 minutes.

8. The method as recited in claim 7, wherein the step f) is carried out at a temperature of 700 to 800°

C. in an O₂ atmosphere for 25 to 35 minutes.

9. The method as recited in claim 8, wherein the step g) is carried out at a temperature of 750°

C. to 850°

C. in an N₂ atmosphere for 25 to 35 minutes.

10. The method as recited in claim 9, wherein the step h) is carried out at a temperature of 700°

C. to 800°

C. in an O₂ atmosphere for 25 to 35 minutes.