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 method of manufacturing a semiconductor device having a capacitance element including a dielectric film disposed between a first electrode layer and a second electrode layer, wherein formation of said capacitance element comprises the steps of:
forming a laminated film comprising at least one pair of amorphous films on said first electrode layer, said amorphous films being a first two-element amorphous metal oxide film and a second two-element amorphous metal oxide film formed in the order named or in the reverse order; wherein said first two-element amorphous metal oxide film and said second two-element amorphous metal oxide film are each deposited to a thickness of one to ten atomic layers, and
heat-treating said laminated film at a temperature close to a crystallization start temperature, thereby converting said laminated film to a single-layer three-element amorphous metal oxide film covering a plurality of crystal grains therein.
2. The method according to claim 1 , wherein said first two-element amorphous metal oxide film is a strontium oxide film and said second two-element amorphous metal oxide film is a titanium oxide film.
3. The method according to claim 2 , wherein said three-element amorphous metal oxide film is a strontium titanate film.
4. The method according to claim 3 , wherein a molar ratio of strontium to titanium in said strontium titanate film is 0.8 to 1.2.
5. The method according to claim 4 , wherein said strontium titanate film is formed by heat-treating said strontium oxide film and said titanium oxide film at a temperature of 500° C. to 600° C.
6. The method according to claim 3 , wherein a molar ratio of strontium to titanium in said strontium titanate film is 0.8 to 1.0.
7. The method according to claim 6 , wherein said strontium titanate film is formed by heat-treating said strontium oxide film and said titanium oxide film at a temperature of 550° C. to 600° C.
8. The method according to claim 1 , further comprising a step of forming an aluminum oxide film between said first two-element amorphous metal oxide film and said first electrode layer or between said second electrode layer and said second two-element amorphous metal oxide film.
9. A method of manufacturing a semiconductor device having a capacitance element including a dielectric film disposed between a first electrode layer and a second electrode layer, wherein formation of said capacitance element comprises the steps of:
forming a laminated film comprising at least one pair of amorphous films on said first electrode layer, 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 in the order named or in the reverse order, and
heat-treating said laminated film at a temperature close to a crystallization start temperature, thereby converting said laminated film to a single-layer amorphous strontium titanate film containing a plurality of crystal grains therein.
10. The method according to claim 9 , 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.
11. The method according to claim 10 , wherein a molar ratio of strontium to titanium in said amorphous strontium titanate film is 0.8 to 1.2.
12. The method according to claim 11 , 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.
13. The method according to claim 10 , wherein a molar ratio of strontium to titanium in said amorphous strontium titanate film is 0.8 to 1.0.
14. The method according to claim 13 , 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.
15. The method according to claim 9 , further comprising a step of forming an aluminum oxide dielectric film between said first electrode layer and said amorphous strontium oxide film or between said second electrode layer and said amorphous titanium oxide film before forming said amorphous strontium oxide film or after forming said amorphous titanium oxide film.