Compositions for thin-film capacitive device, high-dielectric constant insulating film, thin-film capacitance device, and thin-film multilayer ceramic capacitor

• US 20040245561A1
• Filed: 02/26/2004
• Published: 12/09/2004
• Est. Priority Date: 08/28/2001
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Sakashita, Yukio, Funakubo, Hiroshi
• Granted Patent: US 7,242,044 B2
• Time in Patent Office: Days
• US Class Current: 257/310
• CPC Class Codes: B32B 18/00 Layered products essentially comprising ceramics, e.g. refractory products
• CPC Class Codes: C04B 2235/3201 Alkali metal oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3213 Strontium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3227 Lanthanum oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3289 Noble metal oxides
• CPC Class Codes: C04B 2235/963 Surface properties, e.g. surface roughness
• CPC Class Codes: C04B 35/01 based on oxide ceramics
• CPC Class Codes: C04B 35/475 based on bismuth titanates
• CPC Class Codes: H01G 4/10 Metal-oxide dielectrics H01G4/085 takes precedence
• CPC Class Codes: H01G 4/1209 characterised by the ceramic dielectric material H01G4/1272, H01G4/1281 take precedence
• CPC Class Codes: H01G 4/1272 Semiconductive ceramic capacitors
• CPC Class Codes: H01G 4/33 Thin- or thick-film capacitors thin- or thick-film circuits H01L27/00; capacitors without a potential-jump or surface barrier specially adapted for integrated circuits, details thereof, multistep manufacturing processes therefor H01L28/40
• CPC Class Codes: H01L 21/02194 the material containing more than one metal element
• CPC Class Codes: H01L 21/02197 the material having a perovskite structure, e.g. BaTiO3
• CPC Class Codes: H01L 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/02266 deposition by physical ablation of a target, e.g. sputtering, reactive sputtering, physical vapour deposition or pulsed laser deposition
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/31691 with perovskite structure
• CPC Class Codes: H01L 28/55 with a dielectric comprising a perovskite structure material

Abstract

A thin-film capacitor (2) in which a lower electrode (6), a dielectric thin-film (8), and an upper electrode (10) are formed in order on a substrate (4). The dielectric thin-film (8) is made of a composition for thin-film capacitance devices. The composition includes a bismuth layer-structured compound whose c-axis is oriented vertically to the substrate and which is expressed by a formula: (Bi₂O₂)²⁺(A_m−1B_mO_3m+1)²⁻, or Bi₂A_m−1B_mO_3m+3 wherein “m” is an even number, “A” is at least one element selected from Na, K, Pb, Ba, Sr, Ca and Bi, and “B” is at least one element selected from Fe, Co, Cr, Ga, Ti, Nb, Ta Sb, V, Mo and W. The temperature characteristics of the dielectric constant are excellent. Even if the dielectric thin-film is made more thinner, the dielectric constant is relatively high, and the loss is small. The leak characteristics are excellent, the break-down voltage is improved and the surface smoothness is excellent.

Claims

1. A thin-film capacitance device composition including a bismuth layer-structured compound whose c-axis is oriented vertically to a substrate surface, wherein

said bismuth layer-structured compound is expressed by a formula:

(Bi₂O₂)²⁺(A<sub>m−

1</sub>B_mO_3m+1)<sup>2−

or Bi</sup>₂A<sub>m−

1</sub>B_mO_3m+3 in which symbol “

m”

is selected from even numbers, symbol “

A”

is at least one element selected from Na, K, Pb, Ba, Sr, Ca and Bi and symbol “

B”

is at least one element selected from Fe, Co, Cr, Ga, Ti, Nb, Ta, Sb, V, Mo and W.

2. The thin-film capacitance device composition as in claim 1, characterized in degree of c-axis orientation for said bismuth layer-structured compound is 80% or more.

3. The thin-film capacitance device composition as in claim 1 further includes rare-earth element (at least one element selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu).

4. The thin-film capacitance device composition as in claim 3, wherein when said rare-earth element is “

Re” and

said bismuth layer-structured compound is expressed by formula;

Bi₂A<sub>m−

1−

x</sub>Re_xB_mO_3m+3, said “

x”

is 0.01 to 2.0.

5. The thin-film capacitance device composition as in claim 1, wherein “

m”

in the formula composing said bismuth layer-structured compound is any one of 2, 4, 6 and 8.

6. A thin-film capacitance device comprising lower electrode, dielectric thin-film and upper electrode formed one by one on a substrate, wherein said dielectric thin-film is composed of thin-film capacitance device composition, the thin-film capacitance device composition include a bismuth layer-structured compound whose c-axis is oriented vertically to the substrate surface, and

the bismuth layer-structured compound is expressed by a formula:

(Bi₂O₂)²⁺(A<sub>m−

1</sub>B_mO_3m+1)²⁻

or Bi₂A<sub>m−

1</sub>B_mO_3m+3 in which symbol “

m”

is selected from even numbers, symbol “

A”

is at least one element selected from Na, K, Pb, Ba, Sr, Ca and Bi and symbol “

B”

is at least one element selected from Fe, Co, Cr, Ga, Ti, Nb, Ta, Sb, V, Mo and W.

7. The thin-film capacitance device as in claim 6, characterized in degree of c-axis orientation for said bismuth layer-structured compound is 80% or more.

8. The thin-film capacitance device as in claim 6, wherein said thin-film capacitance device composition further includes rare-earth element (at least one element selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu).

9. The thin-film capacitance device as in claim 8, wherein when said rare-earth element is “

Re” and

said bismuth layer-structured compound is expressed by formula;

Bi₂A<sub>m−

1−

x</sub>Re_xB_mO_3m+3, said x is 0.01 to 2.0.

10. The thin-film capacitance device as in claim 6, wherein when temperature is within temperature range of at least −

55°

C. to +150°

C., average change rates (Δ

ε

) of dielectric constant is within ±

20 ppm/°

C. (25°

C. reference temperature).

11. The thin-film capacitance device as in claim 6, wherein said substrate is composed of amorphous material.

12. The thin-film capacitance device as in claim 6, wherein thickness of said dielectric thin-film is 5 to 1000 nm.

13. The thin-film capacitance device as in claim 6, wherein “

m”

in the formula composing said bismuth layer-structured compound is any one of 2, 4, 6 and 8.

14. The thin-film capacitance device as in claim 6, wherein said lower electrode is formed by epitaxial growth on said substrate to [100]orientation.

15. A thin-film multilayer capacitor comprising dielectric thin-films and internal electrode thin-films alternately layered on a substrate, wherein said dielectric thin-films are composed of thin-film capacitance device compositions, the thin-film capacitance device compositions include a bismuth layer-structured compound whose c-axis is oriented vertically to the substrate surface, and said bismuth layer-structured compound is expressed by a formula:

(Bi₂O₂)²⁺(A<sub>m−

1</sub>B_mO_3m+1)²⁻

or Bi₂A<sub>m−

1</sub>B_mO_3m+3 wherein symbol “

m”

is selected from even numbers, symbol “

A”

is at least one element selected from Na, K, Pb, Ba, Sr, Ca and Bi and symbol “

B”

is at least one element selected from Fe, Co, Cr, Ga, Ti, Nb, Ta, Sb, V, Mo and W.

16. The thin-film multilayer capacitor as in claim 15, characterized in degree of c-axis orientation for said bismuth layer-structured compound is 80% or more.

17. The thin-film multilayer capacitor as in claim 15, wherein said thin-film capacitance device composition further includes rare-earth element (at least one element selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu).

18. The thin-film multilayer capacitor as in claim 17, wherein when said rare-earth element is “

Re” and

said bismuth layer-structured compound is expressed by formula;

Bi₂A<sub>m−

1−

x</sub>Re_xB_mO_3m+3, said x is 0.01 to 2.0.

19. The thin-film multilayer capacitor as in claim 15, wherein when temperature is within temperature range of at least −

55°

C. to +150°

C., average change rates (Δ

ε

) of dielectric constant is within ±

120 ppm/°

C (25°

C. reference temperature).

20. The thin-film multilayer capacitor as in claim 15, characterized in said internal electrode thin-film is composed of noble metal, base metal or conductive oxide.

21. The thin-film multilayer capacitor as in claim 15, wherein said substrate is composed of amorphous material.

22. The thin-film multilayer capacitor as in claim 15, wherein thickness of said dielectric thin-film is 5 to 1000 nm.

23. The thin-film multilayer capacitor as in claim 15, wherein “

m”

in the formula composing said bismuth layer-structured compound is any one of 2, 4, 6 and 8.

24. The thin-film multilayer capacitor as in claim 15, wherein said internal electrode thin-film is formed to[100] orientation.

25. A dielectric thin-film composition for capacitor including a bismuth layer-structured compound whose c-axis is oriented vertically to a substrate surface, wherein said bismuth layer-structured compound is expressed by a formula:

(Bi₂O₂)²⁺(A<sub>m−

1</sub>B_mO_3m+1)²⁻

or Bi₂A<sub>m−

1</sub>B_mO_3m+3 in which symbol “

m”

is selected from even numbers, symbol “

A”

is at least one element selected from Na, K, Pb, Ba, Sr, Ca and Bi and symbol “

B”

is at least one element selected from Fe, Co, Cr, Ga, Ti, Nb, Ta, Sb, V, Mo and W.

26. The dielectric thin-film composition for capacitor as in claim 25, characterized in degree of c-axis orientation for said bismuth layer-structured compound is 80% or more.

27. A thin-film capacitor comprising lower electrode, dielectric thin-film and upper electrode formed one by one on a substrate, wherein

said dielectric thin-film is composed of dielectric thin-film composition, the dielectric thin-film composition include a bismuth layer-structured compound whose c-axis is oriented vertically to the substrate surface, and

the bismuth layer-structured compound is expressed by a formula:

(Bi₂O₂)²⁺(A<sub>m−

1</sub>B_mO_3m+1)²⁻

or Bi₂A<sub>m−

1</sub>B_mO_3m+3 wherein symbol “

m”

is selected from even numbers, symbol “

A”

is at least one element selected from Na, K, Pb, Ba, Sr, Ca and Bi and symbol “

B”

is at least one element selected from Fe, Co, Cr, Ga, Ti, Nb, Ta, Sb, V, Mo and W.

28. The thin-film capacitor as in claim 27, characterized in degree of c-axis orientation for said bismuth layer-structured compound is 80% or more.

29. The thin-film capacitor as in claim 27, wherein when temperature is within temperature range of at least −

55°

C. to +150°

C., average change rates (Δ

ε

) of dielectric constant is within ±

120 ppm/°

C. (25°

C. reference temperature).

30. A high-dielectric constant insulating film including a bismuth layer-structured compound whose c-axis is oriented vertically to a substrate surface, wherein

said bismuth layer-structured compound is expressed by a formula:

(Bi₂₀₂)²+(A<sub>m−

1</sub>B_mO_3m+1)²⁻

or Bi₂A<sub>m−

1</sub>B_mO_3m+3 wherein symbol “

m”

is selected from even numbers, symbol “

A”

is at least one element selected from Na, K, Pb, Ba, Sr, Ca and Bi and symbol “

B”

is at least one element selected from Fe, Co, Cr, Ga, Ti, Nb, Ta, Sb, V, Mo and W.

31. The high-dielectric constant insulating film as in claim 30, characterized in degree of c-axis orientation for said bismuth layer-structured compound is 80% or more.

32. The high-dielectric constant insulating film as in claim 30, wherein said bismuth layer-structured compound further include rare-earth element (at least one element selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu).

33. The high-dielectric constant insulating film as in claim 32, wherein when said rare-earth element is “

Re” and

said bismuth layer-structured compound is expressed by formula;

Bi₂A<sub>m−

1−

x</sub>Re_xB_mO_3m+3, said x is 0.01 to 2.0.