Semiconductor device having a capacitance element and method of manufacturing the same
View Patent ↗A dielectric film is formed by depositing an amorphous strontium oxide film to a thickness of one to several atomic layers on a first electrode layer, then depositing an amorphous titanium oxide film to a thickness of one to several atomic layers on the amorphous strontium oxide film, and then heat-treating a laminated film of the amorphous strontium oxide film and the amorphous titanium oxide film at a temperature close to a crystallization start temperature, thereby converting the laminated film to a single-layer amorphous strontium titanate film containing a plurality of crystal grains therein. The laminated film may have a plurality of amorphous strontium oxide films and a plurality of amorphous titanium oxide films that are alternately laminated. A semiconductor device includes a capacitor having as its dielectric film a single-layer amorphous strontium titanate film containing a plurality of crystal grains therein.
1. A semiconductor device having a capacitance element including a dielectric film disposed between a first electrode layer and a second electrode layer,
wherein said dielectric film comprises a single-layer amorphous strontium titanate film covering a plurality of crystal grains wherein said amorphous strontium titanate film is a dielectric film obtained by heat-treating a laminated film comprising at least one pair of amorphous films at a temperature close to a crystallization start temperature of strontium titanate, said amorphous films being an amorphous strontium oxide film having a thickness of one to ten atomic layers and an amorphous titanium oxide film having a thickness of one to ten atomic layers, which are formed on said first electrode layer in the order named or in the reverse order.
2. The semiconductor device according to claim 1 , wherein a molar ratio of strontium to titanium in said amorphous strontium titanate film is 0.8 to 1.2.
3. The semiconductor device according to claim 1 , wherein a molar ratio of strontium to titanium in said amorphous strontium titanate film is 0.8 to 1.0.
4. The semiconductor device according to claim 1 , wherein said laminated film comprises a plurality of pairs each including said amorphous strontium oxide film and said amorphous titanium oxide film and wherein said amorphous strontium oxide films and said amorphous titanium oxide films are alternately laminated.
5. The semiconductor device according to claim 4 , wherein said amorphous strontium titanate film is formed by heat-treating said amorphous strontium oxide films and said amorphous titanium oxide films at a temperature of 500° C. to 600° C.
6. The semiconductor device according to claim 4 , wherein said amorphous strontium titanate film is formed by heat-treating said amorphous strontium oxide films and said amorphous titanium oxide films at a temperature of 550° C. to 600° C.
7. The semiconductor device according to claim 1 , further comprising an aluminum oxide dielectric film between one of said first and second electrode layers and said amorphous strontium titanate film.
8. The semiconductor device according to claim 1 , wherein said capacitance element is included as a capacitor of a memory cell.