Memory of forming a coupling dielectric ta2o5 in a memory device

Abstract

A method of forming a coupling dielectric in a memory cell includes forming an oxide on a substrate, forming Ta 2 O 5 on the oxide, oxidizing the Ta 2 O 5 with rapid thermal process (RTP) at a temperature above the crystallization temperature for Ta 2 O 5 , forming a cell nitride on the oxidized Ta 2 O 5 , and forming a wetgate oxide on the cell nitride.

1 . A method of forming a coupling dielectric in a memory cell comprising: 
 forming an oxide on a substrate;    forming Ta 2 O 5  on the oxide;    oxidizing the Ta 2 O 5  with rapid thermal process (RTP) at a temperature below the crystallization temperature for Ta 2 O 5 ;    forming a cell nitride on the oxidized Ta 2 O 5 ; and    forming a wetgate oxide on the cell nitride.    
   
   
       2 . The method of  claim 1 , wherein oxidizing the Ta 2 O 5  with rapid thermal process (RTP) at the temperature below the crystallization temperature for Ta 2 O 5  comprises: 
 oxidizing the Ta 2 O 5  in rapid thermal process (RTP) in N 2 O at a temperature of between about 400 degrees centigrade and about 725 degrees centigrade.    
   
   
       3 . The method of  claim 2 , further comprising cooling for between about 55 seconds and about 65 seconds after oxidizing the Ta 2 O 5 .  
   
   
       4 . The method of  claim 1 , wherein the steps of forming and oxidizing result in a dielectric stack having a thickness of between 140 angstroms and 240 angstroms.  
   
   
       5 . The method of  claim 1 , wherein oxidizing the Ta 2 O 5  with rapid thermal process (RTP) at the temperature above the crystallization temperature for Ta 2 O 5  comprises oxidizing the Ta 2 O 5  in N 2 O at a temperature of at least about 750 degrees centigrade.  
   
   
       6 . The method of  claim 1 , wherein oxidizing the Ta 2 O 5  with rapid thermal process (RTP) at the temperature above the crystallization temperature for Ta 2 O 5  comprises oxidizing the Ta 2 O 5  in N 2 O at a temperature of less that about 900 degrees centigrade.  
   
   
       7 . The method of  claim 6 , further comprising cooling for between about 55 seconds and about 65 seconds after oxidizing the Ta 2 O 5 .  
   
   
       8 . The method of  claim 1 , wherein forming an oxide on a substrate includes forming the oxide to a depth of about 30 angstroms.  
   
   
       9 . The method of  claim 1 , wherein forming the tantalum oxide includes forming tantalum oxide to a depth of between about 60 angstroms and about 100 angstroms.  
   
   
       10 . A method of forming a coupling capacitor in a memory cell comprising: 
 forming an oxide on a substrate to a depth of about 30 angstroms;    forming a tantalum oxide having a crystallization temperature on the oxide to a depth of between about 60 and about 100 angstroms;    oxidizing the tantalum oxide at a temperature below the crystallization temperature of tantalum oxide;    forming a cell nitride on the oxidized tantalum oxide to a depth of between about 40 angstroms and about 60 angstroms; and    forming a wetgate oxide to a depth of between about 10 angstroms and about 50 angstroms on the cell nitride.    
   
   
       11 . The method of  claim 10 , wherein forming the tantalum oxide on the oxide to the depth of between about 60 and about 100 angstroms comprises forming Ta 2 O 5  on the oxide to a depth of between about 60 angstroms and about 100 angstroms.  
   
   
       12 . The method of  claim 11 , further comprising oxidizing the tantalum oxide in rapid thermal processing (RTP) in N 2 O for about 60 seconds.