Semiconductor device and method for manufacturing the same

• US 20070096180A1
• Filed: 09/21/2006
• Published: 05/03/2007
• Est. Priority Date: 09/21/2005
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Arisumi, Osamu, Hidaka, Osamu, Yamakawa, Koji, Yamazaki, Soichi
• Application Number:
  US11/524,267
• Publication Number:
  US 20070096180A1
• Time in Patent Office: Days
• US Class Current: 257/295
• CPC Class Codes: H01L 28/55 with a dielectric comprising a perovskite structure material
• CPC Class Codes: H01L 28/65 comprising a noble metal or a noble metal oxide, e.g. platinum (Pt), ruthenium (Ru), ruthenium dioxide (RuO2), iridium (Ir), iridium dioxide (IrO2)
• CPC Class Codes: H10B 53/00 Ferroelectric RAM [FeRAM] devices comprising ferroelectric memory capacitors
• CPC Class Codes: H10B 53/30 characterised by the memory core region

Abstract

A semiconductor device includes a semiconductor substrate, and a ferroelectric capacitor provided on the semiconductor substrate, the ferroelectric capacitor comprising a lower electrode, a first ferroelectric film provided on the lower electrode including Pb(Zr_xTi_1-x)O₃ and having a tetragonal crystal system whose crystal direction is oriented in a <111> direction, a second ferroelectric film provided on the first ferroelectric film including Pb(Zr_yTi_1-y)O₃ and having a tetragonal crystal system whose crystal direction is oriented in the <111> direction, and an upper electrode provided on the second ferroelectric film.

Claims

1. A semiconductor device comprising:

a semiconductor substrate; and

a ferroelectric capacitor provided on the semiconductor substrate, the ferroelectric capacitor comprising a lower electrode;

a first ferroelectric film provided on the lower electrode including Pb(Zr_xTi_1-x)O₃ and having a tetragonal crystal system whose crystal direction is oriented in a <

111>

direction;

a second ferroelectric film provided on the first ferroelectric film including Pb(Zr_yTi_1-y)O₃ and having a tetragonal crystal system whose crystal direction is oriented in the <

111>

direction; and

an upper electrode provided on the second ferroelectric film.

2. The semiconductor device according to claim 1,

wherein a x/1−

x ratio of the first ferroelectric film and a y/1−

y ratio of the second ferroelectric film are different from each other.

3. The semiconductor device according to claim 1,

wherein at least the first ferroelectric film among the firs and second ferroelectric film includes dopant.

4. The semiconductor device according to claim 2,

wherein at least the first ferroelectric film among the firs and second ferroelectric film includes dopant.

5. The semiconductor device according to claim 1,

wherein the lower electrode comprises a lower electrode contacting the first ferroelectric film and including SrRuO₃.

6. The semiconductor device according to claim 2,

wherein the lower electrode comprises a lower electrode contacting the first ferroelectric film and including SrRuO₃.

7. The semiconductor device according to claim 3,

wherein the lower electrode comprises a lower electrode contacting the first ferroelectric film and including SrRuO₃.

8. The semiconductor device according to claim 4,

wherein the lower electrode comprises a lower electrode contacting the first ferroelectric film and including SrRuO₃.

9. A method for manufacturing a semiconductor device comprising a semiconductor substrate and a ferroelectric capacitor provided on the semiconductor substrate, the method comprising:

forming the ferroelectric capacitor;

forming a multilayered lower electrode, the multilayered lower electrode including a first conductive film having a (111) plane; and

a second conductive film provided on the first conductive film including SrRuO₃ and being thinner than the first conductive film;

forming a ferroelectric film on the lower electrode, the ferroelectric film including a first ferroelectric film including Pb(Zr_xTi_1-x)O₃ and having a tetragonal crystal system whose crystal direction is oriented in a <

111>

direction; and

a second ferroelectric film provided on the first ferroelectric film including Pb(Zr_yTi_1-y)O₃ and having a tetragonal crystal system whose crystal direction is oriented in the <

111>

direction; and

forming an upper electrode on the ferroelectric film.

10. The method for manufacturing the semiconductor device, according to claim 9,

wherein a x/1−

x ratio of the first ferroelectric film and a y/1−

y ratio of the second ferroelectric film are different from each other.

11. The method for manufacturing the semiconductor device, according to claim 9,

wherein at least the first ferroelectric film among the firs and second ferroelectric film includes dopant.

12. The method for manufacturing the semiconductor device, according to claim 10,

wherein at least the first ferroelectric film among the firs and second ferroelectric film includes dopant.