Ferroelectric memory device and method of manufacturing the same

Abstract

A ferroelectric memory device includes: a substrate; a ferroelectric capacitor which is formed on the substrate and includes a lower electrode, a ferroelectric film, and an upper electrode; a hydrogen barrier film provided to cover the ferroelectric capacitor; and an interlayer dielectric provided on the hydrogen barrier film. A thickness of an area of the hydrogen barrier film provided on the upper electrode is greater than a thickness of an area of the hydrogen barrier film provided on a sidewall of the ferroelectric capacitor.

1 . A ferroelectric memory device, comprising: 
 a substrate;    a ferroelectric capacitor which is formed on the substrate and includes a lower electrode, a ferroelectric film, and an upper electrode;    a hydrogen barrier film provided to cover the ferroelectric capacitor; and    an interlayer dielectric provided on the hydrogen barrier film,    wherein a thickness of an area of the hydrogen barrier film provided on the upper electrode is greater than a thickness of an area of the hydrogen barrier film provided on a sidewall of the ferroelectric capacitor.    
   
   
       2 . The ferroelectric memory device as defined in  claim 1 , 
 wherein an area of an upper surface of the ferroelectric film is greater than an area of an interface between the ferroelectric film and the upper electrode.    
   
   
       3 . The ferroelectric memory device as defined in  claim 1 , 
 wherein the hydrogen barrier film includes:    a first hydrogen barrier film provided on the upper electrode; and    a second hydrogen barrier film provided on the first hydrogen barrier film and in a region including the sidewall of the ferroelectric capacitor.    
   
   
       4 . The ferroelectric memory device as defined in  claim 2 , 
 wherein the hydrogen barrier film includes:    a first hydrogen barrier film provided on the upper electrode;    a second hydrogen barrier film provided on the first hydrogen barrier film and the ferroelectric film; and    a third hydrogen barrier film provided on the second hydrogen barrier film and in a region including the sidewall of the ferroelectric capacitor.    
   
   
       5 . The ferroelectric memory device as defined in  claim 1 , 
 wherein the hydrogen barrier film is formed by using an atomic-layer CVD (ALCVD) method.    
   
   
       6 . The ferroelectric memory device as defined in  claim 1 , 
 wherein the hydrogen barrier film is an oxide including one or more elements selected from aluminum, titanium, hafnium, zirconium, magnesium, and tantalum.    
   
   
       7 . A method of manufacturing a ferroelectric memory device, the method comprising: 
 forming a hydrogen barrier film which covers a ferroelectric capacitor including a lower electrode, a ferroelectric film, and an upper electrode,    wherein a thickness of an area of the hydrogen barrier film provided on the upper electrode is made greater than a thickness of an area of the hydrogen barrier film provided on a sidewall of the ferroelectric capacitor by forming the area of the hydrogen barrier film provided on the upper electrode in a plurality of layers.    
   
   
       8 . A method of manufacturing a ferroelectric memory device, the method comprising: 
 (a) forming a lower electrode, a ferroelectric film, and an upper electrode on a substrate in layers in that order;    (b) forming a first hydrogen barrier film on the upper electrode;    (c) patterning the first hydrogen barrier film, the upper electrode, the ferroelectric film, and the lower electrode to form a ferroelectric capacitor; and    (d) forming a second hydrogen barrier film which covers the ferroelectric capacitor.    
   
   
       9 . A method of manufacturing a ferroelectric memory device, the method comprising: 
 (a) forming a lower electrode, a ferroelectric film, and an upper electrode on a substrate in layers in that order;    (b) patterning the upper electrode;    (c) forming a first hydrogen barrier film on the upper electrode and the ferroelectric film;    (d) patterning the first hydrogen barrier film, the ferroelectric film, and the lower electrode to have an area greater than an area of the upper electrode to form a ferroelectric capacitor; and    (e) forming a second hydrogen barrier film which covers the ferroelectric capacitor.    
   
   
       10 . A method of manufacturing a ferroelectric memory device, the method comprising: 
 (a) forming a lower electrode, a ferroelectric film, and an upper electrode on a substrate in layers in that order;    (b) forming a first hydrogen barrier film on the upper electrode;    (c) patterning the first hydrogen barrier film and the upper electrode;    (d) forming a second hydrogen barrier film on the first hydrogen barrier film and the ferroelectric film;    (e) patterning the second hydrogen barrier film, the ferroelectric film, and the lower electrode to have an area greater than an area of the upper electrode to form a ferroelectric capacitor; and    (f) forming a third hydrogen barrier film which covers the ferroelectric capacitor.    
   
   
       11 . The method of manufacturing a ferroelectric memory device as defined in  claim 8 , 
 wherein the first hydrogen barrier film is formed by using the same method as the upper electrode.    
   
   
       12 . The method of manufacturing a ferroelectric memory device as defined in  claim 9 , 
 wherein the first hydrogen barrier film is formed by using the same method as the upper electrode.    
   
   
       13 . The method of manufacturing a ferroelectric memory device as defined in  claim 7 , 
 wherein at least one of the hydrogen barrier films is formed by using an atomic-layer CVD (ALCVD) method.    
   
   
       14 . The method of manufacturing a ferroelectric memory device as defined in  claim 8 , 
 wherein at least one of the first and second hydrogen barrier films is formed by using an atomic-layer CVD (ALCVD) method.    
   
   
       15 . The method of manufacturing a ferroelectric memory device as defined in  claim 9 , 
 wherein at least one of the first and second hydrogen barrier films is formed by using an atomic-layer CVD (ALCVD) method.    
   
   
       16 . The method of manufacturing a ferroelectric memory device as defined in  claim 10 , 
 wherein at least one of the first, second, and third hydrogen barrier films is formed by using an atomic-layer CVD (ALCVD) method.    
   
   
       17 . The method of manufacturing a ferroelectric memory device as defined in  claim 13 , 
 wherein ozone is used as an oxidizing agent for a metal element to be supplied in the ALCVD method.    
   
   
       18 . The method of manufacturing a ferroelectric memory device as defined in  claim 14 , 
 wherein ozone is used as an oxidizing agent for a metal clement to be supplied in the ALCVD method.    
   
   
       19 . The method of manufacturing a ferroelectric memory device as defined in  claim 15 , 
 wherein ozone is used as an oxidizing agent for a metal element to be supplied in the ALCVD method.    
   
   
       20 . The method of manufacturing a ferroelectric memory device as defined in  claim 16 , 
 wherein ozone is used as an oxidizing agent for a metal element to be supplied in the ALCVD method.