Semiconductor device and method of manufacturing the same
View Patent ↗A semiconductor device includes a ferroelectric capacitor formed over a semiconductor substrate, wherein the ferroelectric capacitor including a lower electrode, a ferroelectric film formed on the lower electrode, and an upper electrode formed on the ferroelectric film, and the upper electrode including a first conductive film formed of a first conductive noble metal oxide, and a second conductive film formed of a metal nitride compound formed on the first conductive film.
1. A semiconductor device, comprising:
a ferroelectric capacitor, formed over a semiconductor substrate, including a lower electrode, a ferroelectric film formed on the lower electrode, and an upper electrode formed on the ferroelectric film,
wherein the upper electrode includes
a first conductive film formed of first conductive noble metal oxide and formed over the ferroelectric film,
a second conductive film formed of metal nitride compound and formed over the first conductive film, and
a fourth conductive film formed of a second conductive metal oxide and formed between the first conductive film and the second conductive film, and an oxidation composition of the fourth conductive film is larger than an oxidation composition of the first conductive film.
2. The semiconductor device according to claim 1 , wherein the metal nitride compound includes a metallic element that is different from a metallic element in the first conductive noble metal oxide.
3. The semiconductor device according to claim 1 , wherein the upper electrode has a third conductive film formed of noble metal and formed between the fourth conductive film and the second conductive film.
4. The semiconductor device according to claim 3 , wherein the first conductive noble metal oxide includes a metallic element same as the noble metal included in the third conductive film.
5. The semiconductor device according to claim 3 , wherein the first conductive noble metal oxide includes a metallic element different from the noble metal included in the third conductive film.
6. The semiconductor device according to 1 , wherein the metal nitride compound is a nitride compound including two or more metallic elements.
7. The semiconductor device according to claim 1 , wherein the fourth conductive film and the first conductive film have same noble metallic element.
8. The semiconductor device according to claim 1 , wherein the fourth conductive film and the first conductive film have different noble metallic element.
9. The semiconductor device according to claim 1 , wherein
the first conductive film is formed of a first oxide film whose composition is expressed by a chemical formula AO x1 (A: metallic element, O: oxygen) using an initial composition parameter x 1 , and whose composition is expressed by a chemical formula AO x2 using an actual composition parameter x 2 , and
the fourth conductive film is formed of a second oxide film which is formed on the first conductive film, whose composition is expressed by a chemical formula BO y1 (B: metallic element, O: oxygen) using an initial composition parameter y 1 , and whose composition is expressed by a chemical formula BO y2 using an actual composition parameter y 2 , which includes at least one of stone-wall crystal and column crystal, and in which a degree of oxidation is set higher than the first oxide film, whereby a relation Y 2 /y 1 >x 2 /x 1 is satisfied between the composition parameters x 1 , x 2 , y 1 , and y 2 .
10. The semiconductor device according to claim 1 , wherein a metallic element included in at least one of the first conductive film and the fourth conductive film is iridium or ruthenium.
11. The semiconductor device according to claim 1 , wherein the second conductive film is formed of at least one of a TiAlN film, a TiAlON film, a TaAlN film, and a TaAlON film.
12. The semiconductor device according to claim 3 , wherein the third conductive film is formed of at least one of an iridium film, a platinum film, a ruthenium film, a rhodium film, and a palladium film.