Capacitor with high dielectric constant materials and method of making

Abstract

Stabilized capacitors and DRAM cells using high dielectric constant oxide dielectric materials such as Ta 2 O 5 and Ba x Sr (1-x) TiO 3 , and methods of making such capacitors and DRAM cells are provided. One method includes providing a conductive oxide electrode, oxidizing at least the upper surface of the conductive oxide electrode, depositing a first layer of a high dielectric constant oxide dielectric material on the conductive oxide electrode, oxidizing the first layer of the high dielectric constant oxide dielectric material under oxidizing conditions, depositing a second layer of the high dielectric constant oxide dielectric material on the first layer of the dielectric, and depositing an upper layer electrode on the second layer of the high dielectric constant oxide dielectric material.

1 . A method of forming a capacitor comprising providing a conductive oxide electrode, oxidizing at least the upper surface of said conductive oxide electrode, depositing a first layer of a high dielectric constant oxide dielectric material on said conductive oxide electrode, oxidizing said first layer of said high dielectric constant oxide dielectric material under oxidizing conditions, depositing a second layer of said high dielectric constant oxide dielectric material on said first layer of said high dielectric constant oxide dielectric material, and depositing an upper layer electrode on said second layer of said high dielectric constant oxide dielectric material.  
   
   
       2 . A method as claimed in  claim 1  wherein said high dielectric constant oxide dielectric material is oxidized using a gas plasma.  
   
   
       3 . A method as claimed in  claim 2  wherein said gas plasma is formed from a gas selected from the group consisting of O 2  and O 3 .  
   
   
       4 . A method as claimed in  claim 2  wherein the gas plasma oxidation is carried out at a temperature in the range of from about 250° to about 500° C.  
   
   
       5 . A method as claimed in  claim 1  wherein said high dielectric constant oxide dielectric material is Ta 2 O 5 .  
   
   
       6 . A method as claimed in  claim 5  wherein said high dielectric constant oxide dielectric material is amorphous Ta 2 O 5 .  
   
   
       7 . A method as claimed in  claim 5  wherein said high dielectric constant oxide dielectric material is crystalline Ta 2 O 5 .  
   
   
       8 . A method as claimed in  claim 1  wherein said conductive oxide electrode comprises RuO x .  
   
   
       9 . A method of forming a capacitor comprising providing a conductive oxide electrode, depositing a first layer of a high dielectric constant oxide dielectric material on said conductive oxide electrode, oxidizing said conductive oxide electrode and said first layer of said high dielectric constant oxide dielectric material under oxidizing conditions, depositing a second layer of said high dielectric constant oxide dielectric material on said first layer of said high dielectric constant oxide dielectric material, depositing an upper layer electrode on said second layer of said high dielectric constant oxide dielectric material, depositing a gas permeable electrode on said upper layer electrode, and oxidizing said upper layer electrode through said gas permeable electrode; wherein said upper layer electrode is oxidized by annealing under oxidizing conditions.  
   
   
       10 . A method as claimed in  claim 9  wherein said upper electrode is annealed at a temperature in the range of from about 350° to about 500° C.  
   
   
       11 . A method of forming a capacitor comprising providing a conductive oxide electrode, oxidizing at least the upper surface of said conductive oxide electrode, depositing a first layer of a high dielectric constant oxide dielectric material comprising Ta 2 O 5  on the conductive oxide electrode, oxidizing said first layer of said high dielectric constant oxide dielectric material under oxidizing conditions, depositing a second layer of said high dielectric constant oxide dielectric material on said first layer of said high dielectric constant oxide dielectric material, oxidizing said second layer of said high dielectric constant oxide dielectric material, and depositing an upper layer electrode on said second layer of said high dielectric constant oxide dielectric material.  
   
   
       12 . A method as claimed in  claim 11  wherein said second layer of said high dielectric constant oxide dielectric material is oxidized using a gas plasma.  
   
   
       13 . A method as claimed in  claim 12  wherein said gas plasma is formed using a gas selected from the group consisting of O 2  and O 3 .  
   
   
       14 . A method as claimed in  claim 12  wherein said gas plasma oxidation is carried out at a temperature in the range of from about 300° to about 700° C.  
   
   
       15 . A method as claimed in  claim 11  wherein said second layer of said high dielectric constant oxide dielectric material is oxidized in a furnace.  
   
   
       16 . A method as claimed in  claim 15  wherein the furnace oxidation is performed at a temperature of less than about 700° C.  
   
   
       17 . A method as claimed in  claim 15  wherein the furnace oxidation uses a gas selected from the group consisting of O 2  and N 2 O.  
   
   
       18 . A method as claimed in  claim 11  wherein said second layer of said high dielectric constant oxide dielectric material is oxidized by rapid thermal oxidation.  
   
   
       19 . A method as claimed in  claim 18  wherein the rapid thermal oxidation is performed at a temperature of less than about 700° C.  
   
   
       20 . A method as claimed in  claim 18  wherein the oxidation is performed in the presence of a gas selected from the group consisting of O 2  and N 2 O.  
   
   
       21 . A method as claimed in  claim 11  further comprising crystallizing said second layer of said high dielectric constant oxide dielectric material prior to depositing said upper electrode.  
   
   
       22 . A method as claimed in  claim 21  wherein said second layer of said high dielectric constant oxide dielectric material is crystallized by heating said high dielectric constant oxide dielectric material at a temperature greater than about 700° C. in an inert atmosphere.  
   
   
       23 . A method as claimed in  claim 21  wherein said second layer of said high dielectric constant oxide dielectric material is crystallized and oxidized by heating said high dielectric constant oxide dielectric material at a temperature greater than about 700° C. in an atmosphere containing a gas selected from the group consisting of O 2  and N 2 O.  
   
   
       24 . A method as claimed in  claim 11  wherein said conductive oxide electrode comprises RuO x .  
   
   
       25 . A method of forming a capacitor comprising providing a conductive oxide electrode, oxidizing at least the upper surface of said conductive oxide electrode, depositing a first layer of a dielectric material comprising Ta 2 O 5  on said conductive oxide electrode, treating said dielectric material under oxidizing conditions, depositing a second layer of a dielectric material comprising Ta 2 O 5  on said first layer of said dielectric material, oxidizing said second layer of said dielectric material, crystallizing said second layer of said dielectric material, and depositing an upper layer electrode on said second layer of said dielectric material.  
   
   
       26 . A method as claimed in  claim 25  wherein said second layer of said dielectric material is crystallized by heating at a temperature of greater than about 700° C. in an inert atmosphere.  
   
   
       27 . A method as claimed in  claim 25  wherein said second layer of said dielectric material is crystallized and oxidized by heating at a temperature of greater than about 700° C. in an atmosphere containing a gas selected from the group consisting of O 2  and N 20 .  
   
   
       28 . A method as claimed in  claim 25  wherein said second layer of said dielectric material is oxidized by a gas plasma.  
   
   
       29 . A method as claimed in  claim 28  wherein said gas plasma oxidation is carried out in a gas selected from the group consisting of O 2  and O 3 .  
   
   
       30 . A method as claimed in  claim 28  wherein said gas plasma oxidation is carried out at a temperature in the range of from about 300° to about 700° C.  
   
   
       31 . A method as claimed in  claim 25  wherein said second layer of said dielectric material is oxidized in a furnace.  
   
   
       32 . A method as claimed in  claim 31  wherein the furnace oxidation is carried out at a temperature less than about 700° C.  
   
   
       33 . A method as claimed in  claim 31  wherein the furnace oxidation is carried out in an atmosphere containing a gas selected from the group consisting of O 2  and N 20 .  
   
   
       34 . A method as claimed in  claim 25  wherein said second layer of said dielectric material is oxidized by rapid thermal oxidation.  
   
   
       35 . A method as claimed in  claim 34  wherein said rapid thermal oxidation is carried out at a temperature of less than about 700° C.  
   
   
       36 . A method as claimed in  claim 34  wherein said rapid thermal oxidation is carried out in an atmosphere containing a gas selected from the group consisting of O 2  and N 2 O.  
   
   
       37 . A method as claimed in  claim 25  wherein said conductive oxide electrode comprises RuO x .  
   
   
       38 . A method of forming a capacitor comprising providing a conductive oxide electrode selected from the group consisting of RuO x  and IrO x , depositing a first layer of a dielectric material selected from the group consisting of Ta 2 O 5  and Ba x Sr (1-x) TiO 3  on said conductive oxide electrode, oxidizing said conductive oxide electrode and said first layer of said dielectric material using a gas plasma under oxidizing conditions, depositing a second layer of said dielectric material on said first layer of said dielectric material, oxidizing said second layer of said dielectric material with a gas plasma, depositing an upper layer electrode on said second layer of said dielectric material, and oxidizing said upper layer electrode.  
   
   
       39 . A method as claimed in  claim 38  wherein said gas plasma is formed from a gas selected from the group consisting of O 2  and O 3 .  
   
   
       40 . A method as claimed in  claim 38  wherein said oxidation is carried out at a temperature in the range of from about 250° to about 500° C.  
   
   
       41 . A method as claimed in  claim 38  wherein said second layer of said dielectric material is oxidized in a furnace.  
   
   
       42 . A method as claimed in  claim 41  wherein said furnace oxidation is carried out at a temperature of less than about 700° C.  
   
   
       43 . A method as claimed in  claim 41  wherein said furnace oxidation is carried out in an atmosphere comprising a gas selected from the group consisting of O 2  and N 2 O.  
   
   
       44 . A method as claimed in  claim 38  further comprising depositing a gas permeable electrode on said upper layer electrode prior to oxidizing said upper layer electrode; wherein said upper layer electrode is oxidized by annealing under oxidizing conditions.  
   
   
       45 . A method as claimed in  claim 44  wherein the annealing is carried out at a temperature in the range of from about 350° to about 500° C.  
   
   
       46 . A method of forming a capacitor comprising providing a conductive oxide electrode, depositing a first layer of a Ba x Sr (1-x) TiO 3  dielectric material on said conductive oxide electrode, oxidizing said conductive oxide electrode and said first layer of said dielectric material with a gas plasma under oxidizing conditions, depositing a second layer of said dielectric material on said first layer of said dielectric material, depositing an upper layer electrode on said second layer of said dielectric material, and oxidizing said upper layer electrode.  
   
   
       47 . A method as claimed in  claim 46  wherein said first layer of said dielectric material is deposited at a temperature of less than about 650° C.  
   
   
       48 . A method as claimed in  claim 46  wherein said first layer of said dielectric material is deposited at a temperature in the range of from about 400° to about 500° C.  
   
   
       49 . A method as claimed in  claim 46  wherein said conductive oxide electrode is selected from the group consisting of RuO x  and IrO x .  
   
   
       50 . A method as claimed in  claim 46  wherein said first layer of said dielectric material is deposited at a temperature of less than about 650° C.  
   
   
       51 . A method as claimed in  claim 46  wherein said second layer of said dielectric material is deposited at a temperature in the range of from about 550° to about 600° C.  
   
   
       52 . A method as claimed in  claim 46  wherein said upper layer electrode is selected from the group consisting of RuO x  and IrO x .  
   
   
       53 . A method of forming a DRAM cell comprising providing a conductive oxide electrode, depositing a first layer of a high dielectric constant oxide dielectric material on said conductive oxide electrode, oxidizing said conductive oxide electrode and said first layer of said high dielectric constant oxide dielectric material under oxidizing conditions, depositing a second layer of said high dielectric constant oxide dielectric material on said first layer of said high dielectric constant oxide dielectric material, depositing an upper layer electrode on said second layer of said high dielectric constant oxide dielectric material, providing a field effect transistor having a pair of source/drain regions, electrically connecting one of said source/drain regions with said conductive oxide electrode and electrically connecting the other of said source/drain regions with a bit line.  
   
   
       54 . A method as claimed in  claim 53  wherein said high dielectric constant oxide dielectric material is oxidized using a gas plasma.  
   
   
       55 . A method as claimed in  claim 54  wherein said gas plasma is formed from a gas selected from the group consisting of O 2  and O 3 .  
   
   
       56 . A method as claimed in  claim 54  wherein the gas plasma oxidation is carried out at a temperature in the range of from about 250° to about 500° C.  
   
   
       57 . A method as claimed in  claim 54  wherein said high dielectric constant oxide dielectric material is Ta 2 O 5 .  
   
   
       58 . A method as claimed in  claim 57  wherein said high dielectric constant oxide dielectric material is amorphous Ta 2 O 5 .  
   
   
       59 . A method as claimed in  claim 57  wherein said high dielectric constant oxide dielectric material is crystalline Ta 2 O 5 .