Semiconductor device and method of manufacturing the same

Abstract

A semiconductor device comprising a substrate and a ferroelectric capacitor formed on the substrate. The ferroelectric capacitor includes a lower electrode, an upper electrode and a ferroelectric film interposed between the lower and upper electrodes. The ferroelectric capacitor having sidewalls receded from sidewalls of the upper electrode.

1 . A semiconductor device comprising:
 a substrate; and   a ferroelectric capacitor provided on the substrate and fabricated by forming a lower electrode, a ferroelectric film and a mask-material film on a part of the substrate, by making an opening in the mask-material film and by burying the upper electrode in the opening.   
   
   
       2 . The semiconductor device according to  claim 1 , wherein the substrate is a semiconductor substrate. 
   
   
       3 . The semiconductor device according to  claim 2 , further comprising: a switching transistor provided on the substrate, and an interlayer insulating film provided on the substrate, covering the transistor, and in which the ferroelectric capacitor is provided on the interlayer insulating film. 
   
   
       4 . The semiconductor device according to  claim 1 , wherein the mask-material film is made of alumina (Al 2 O 3 ), zirconium oxide (ZrO 2 ), aluminium silicon oxide (AlSiO), silicon oxide (SiO 2 ), titanium oxide (TiO 2 ) or may be a multi-layer structure composed of films of these oxides. 
   
   
       5 . The semiconductor device according to  claim 1 , wherein the sidewalls of the lower electrode and the sidewalls of the ferroelectric film have surfaces which line on lines extending in the sidewalls surfaces of the mask-material film. 
   
   
       6 . The semiconductor device according to  claim 1 , wherein that part of the ferroelectric film, which contacts the upper electrode, is 1 nm or more thinner than the other part. 
   
   
       7 . A semiconductor device comprising:
 a substrate;   a ferroelectric capacitor provided on the substrate and comprising a lower electrode, an upper electrode and a ferroelectric film interposed between the upper and lower electrodes, said upper electrode being provided in a region inner of a peripheral region of the ferroelectric film; and   a mask-material film provided on the ferroelectric film and surrounding the peripheral region of the upper electrode.   
   
   
       8 . The semiconductor device according to  claim 7 , wherein the substrate is a semiconductor substrate. 
   
   
       9 . The semiconductor device according to  claim 8 , further comprising: a switching transistor provided on the substrate, and an interlayer insulating film provided on the substrate, covering the transistor, and in which the ferroelectric capacitor is provided on the interlayer insulating film. 
   
   
       10 . The semiconductor device according to  claim 7 , wherein the mask-material film is made of alumina (Al 2 O 3 ), zirconium oxide (ZrO 2 ), aluminium silicon oxide (AlSiO), silicon oxide (SiO 2 ), titanium oxide (TiO 2 ) or may be a multi-layer structure composed of films of these oxides. 
   
   
       11 . The semiconductor device according to  claim 7 , wherein the sidewalls of the lower electrode and the sidewalls of the ferroelectric film have surfaces which lie on lines extending in the sidewalls surfaces of the mask-material film. 
   
   
       12 . The semiconductor device according to  claim 7 , wherein that part of the ferroelectric film, which contacts the upper electrode, is 1 nm or more thinner than the other part.