Claims
- 1. A ferro-electric capacitor comprising:a first electrode comprising at least a layer of a conductive oxide having at least two sub-layers of individual grains, wherein individual grains of a top sub-layer of the two sub-layers are oriented randomly; a second electrode that is isolated from said first electrode; and a ferro-electric PZT layer that is sandwiched between said first electrode and said second electrode.
- 2. The ferro-electric capacitor of claim 1, wherein said conductive layer comprises a micro- or a nano-crystalline structure.
- 3. The ferro-electric capacitor claim 2, wherein said conductive oxide layer comprises a grain size that is at most 50 nm.
- 4. The ferro-electric capacitor of claim 3, wherein the grain size is at most 20 nm.
- 5. The ferro-electric capacitor of claim 1, wherein said conductive oxide layer (34) comprises a unary oxide having a rutile crystal structure selected from the group consisting of IrO2, RuO2, RhO2, ReO2 and OsO2.
- 6. The ferro-electric capacitor of claim 1, wherein said conductive oxide layer comprises a complex oxide having a perovskite crystal layer of (La,Sr)CoO3.
- 7. The ferro-electric capacitor of claim 1, wherein said PZT layer comprises a (111)-orientation.
- 8. The ferro-electric capacitor of claim 1, wherein the capacitor is connected to an electrode of an active device via a connection portion.
- 9. The ferro-electric capacitor of claim 1, wherein said PZT layer comprises one horizontal surface having side walls that overlap with said first electrode.
- 10. A method of growing a PZT layer on a conductive oxide layer formed on a substrate, the method comprising:forming at least two sub-layers of individual grains to comprise said oxide layer; causing the top sub-layer of the two sub-layers to have a random orientation; and placing a PZT layer between the two sub-layers and an electrode that is isolated from the two sub-layers.
- 11. The method of claim 10, further comprising forming the grain size of said conductive oxide layer to be between one-fifth and one-half the thickness of the PZT layer.
- 12. The method of claim 11, wherein the temperature of the substrate during the growing of the PZT layer ranges between a first predetermined temperature Tc1 and a second predetermined temperature Tc2, wherein Tc1 being defined by the temperature below which the sub-layers of the conductive oxide layer becomes amorphous, and Tc2 being defined by the temperature at which the grain size of the PZT layer is within a predetermined dimension of about 20 nm.
- 13. The method of claim 11, wherein the atmosphere during the growing of the PZT layer comprises an O2/Ar mixture having a ratio of at least 1.
- 14. The method of claim 11, wherein the deposition rate of the PZT layer during the growth is in the range of 15-20 nm/min.
Priority Claims (1)
Number |
Date |
Country |
Kind |
99870224 |
Oct 1999 |
EP |
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RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 09/857,320, filed on Aug. 31, 2001, entitled “METHOD OF FABRICATION OF A FERRO-ELECTRIC CAPACITOR AND METHOD OF GROWING A PZT LAYER ON A SUBSTRATE” now U.S. Pat. No. 6,545,856, which is a U.S. national stage application of International Application No. PCT/BE99/00155 having an international filing date of Nov. 30, 1999, which claims priority to European Application No. 99870224.5, filed on Oct. 26, 1999, and to U.S. Provisional Application No. 60/110,276, filed on Nov. 30, 1998. The International Application published in the English language as International Publication No. WO 00/33361 on Jun. 8, 2000.
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Number |
Name |
Date |
Kind |
5555486 |
Kingon et al. |
Sep 1996 |
A |
6072689 |
Kirlin |
Jun 2000 |
A |
Provisional Applications (1)
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Number |
Date |
Country |
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60/110276 |
Nov 1998 |
US |
Continuations (1)
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Number |
Date |
Country |
Parent |
09/857320 |
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US |
Child |
10/349512 |
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US |