Ceramic composition and ceramic capacitor

FIELD OF THE INVENTION

[0001] The present invention relates to a ceramic capacitor and ceramic compositions therefor; and, more particularly, to reduction resistive dielectric ceramic compositions suitable for use as a dielectric layer of a ceramic capacitor having internal electrodes made of a base metal such as Ni and a ceramic capacitor fabricated by employing such ceramic compositions as a dielectric layer thereof.

BACKGROUND OF THE INVENTION

[0002] Recently, a base metal, e.g., Ni, is widely used in forming internal electrodes of multilayer ceramic capacitors for the purpose of reducing manufacturing costs. In case the internal electrodes are composed of the base metal, it is required that chip-shaped laminated bodies including therein the internal electrodes be sintered in a reductive atmosphere in order to prevent an oxidization of the internal electrodes. Accordingly, a variety of reduction resistive dielectric ceramic compositions have been developed.

[0003] Recent trend towards ever more miniaturized and dense electric circuits intensifies a demand for a further scaled down multilayer ceramic capacitor with higher capacitance. Keeping up with such demand, there has been made an effort to fabricate thinner dielectric layers and to stack a greater number of the thus produced dielectric layers.

[0004] However, when the dielectric layers are thinned out, a voltage applied to a unit thickness intrinsically increases. Accordingly, the operating life of the dielectric layers is shortened and thus a reliability of the multilayer ceramic capacitor is also deteriorated.

SUMMARY OF THE INVENTION

[0005] It is, therefore, an object of the present invention to provide highly reliable dielectric ceramic compositions and ceramic capacitors prepared by employing such dielectric ceramic compositions in forming dielectric layers thereof, wherein the dielectric ceramic compositions exhibit such electrical characteristics as a dielectric contstant equal to or greater than 3000, capacitance variation of −15% to +15% (based on a capacitance obtained at a temperature of +25° C.) in the temperature range from −55° C. to +125° C., a dielectric loss “tanδ” of 3.5% or less and an accelerated life of 200,000 seconds or greater.

[0006] In accordance with the present invention, there is provided a dielectric ceramic composition comprising: 100 mol % of oxides of Ba and Ti, a ratio Ba/Ti being 0.970 to 1.030; 0.25 to 1.5 mol % of an oxide of Re, Re representing one or more elements selected from the group consisting of Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Y; 0.2 to 1.5 mol % of an oxide of Mg; and 0.03 to 0.6 mol % of oxides of one or more elements selected from the group consisting of Mn, V and Cr.

BRIEF DESCRIPTION OF THE DRAWING

[0007] The above and other objects and features of the present invention will become apparent from the following description of preferred embodiments given in conjunction with the accompanying drawing:

[0008] Drawing represents a schematic cross sectional view illustrating a multilayer ceramic capacitor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Compound powders of TiO2, BaCO3, Re2O3, MgO, Mn2O3, V2O5, Cr2O3, MoO3 and WO3 were weighed in amounts as specified in the accompanying Tables 1-1 and 1-6, and mixed for about 20 hours by a wet method in a ball mill containing therein PSZ (partially sterilized zirconia) balls and water to thereby obtain a ceramic slurry. The produced ceramic slurry was dehydrated and then dried by being heated at about 150° C. for 6 hours.

1TABLE 1-1Dielectric Composition (mol %)Rare-earthSample(Re2O3)TotalBa/TiNumberElementContentMgOMn2O3V2O5Cr2O3ContentMoO3Ratio 1 &Asteriskpseud;Ho0.750.40.020.020.051.0050 2 &Asteriskpseud;Ho0.750.40.020.020.051.0050 3 &Asteriskpseud;Ho0.750.40.020.020.051.0050 4Ho0.750.40.030.030.051.0050 5Ho0.750.40.030.030.051.0050 6Ho0.750.40.030.030.051.0050 7Ho0.750.40.010.020.030.051.0050 8Ho0.750.40.050.020.070.051.0050 9Ho0.750.40.050.20.250.051.005010Ho0.750.40.050.010.20.260.051.005011Ho0.750.40.050.050.20.30.051.005012Ho0.750.40.20.20.20.60.051.005013Ho0.750.40.60.60.051.005014Ho0.750.40.60.60.051.005015Ho0.750.40.60.60.051.005016 &Asteriskpseud;Ho0.750.40.70.70.051.005017 &Asteriskpseud;Ho0.750.40.70.70.051.005018 &Asteriskpseud;Ho0.750.40.70.70.051.005019Ho0.750.40.050.10.10.2501.005020Ho0.750.40.050.10.10.250.0251.005021Ho0.750.40.050.10.10.250.11.005022Ho0.750.40.050.10.10.250.21.005023Ho0.750.40.050.10.10.250.31.005024 &Asteriskpseud;Ho0.750.40.050.10.10.250.41.005025Ho0.750.40.0250.050.20.2750.051.005026 &Asteriskpseud;Ho0.000.40.150.050.20.40.051.005027Ho0.250.40.150.050.20.40.051.005028Ho0.50.40.150.050.20.40.051.005029Ho1.00.40.150.050.20.40.051.0050

[0010]

2

TABLE 1-2

Dielectric Composition (mol %)

Rare-earth

Sample
(Re2O3)

Total

Ba/Ti

Number
Element
Content
MgO
Mn2O3
V2O5
Cr2O3
Content
MoO3
Ratio

30
Ho
1.5
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

31 &Asteriskpseud;
Ho
2.0
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

32 &Asteriskpseud;
Ho
4.0
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

33
Sm
0.25
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

34
Sm
0.75
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

35
Eu
0.75
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

36
Gd
0.75
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

37
Tb
0.75
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

38
Dy
0.75
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

39
Er
0.75
0.3
0.15
0.05
0.2
0.4
0.05
1.0050

40
Tm
0.75
0.3
0.15
0.05
0.2
0.4
0.05
1.0050

41
Yb
0.75
0.3
0.15
0.05
0.2
0.4
0.05
1.0050

42
Yb
1.0
0.3
0.15
0.05
0.2
0.4
0.05
1.0050

43
Y
1.0
0.3
0.15
0.05
0.2
0.4
0.05
1.0050

44
Ho/Dy
0.5/0.5
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

45
Ho/Dy/Yb
0.5/0.5/0.5
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

46
Sm/Ho/Yb
0.2/0.5/0.1
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

47
Sm/Yb
0.5/1.0
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

48 &Asteriskpseud;
Ho
0.75
0
0.15
0.05
0.2
0.4
0.05
1.0050

49
Ho
0.75
0.2
0.15
0.05
0.2
0.4
0.05
1.0050

50
Ho
0.75
1.5
0.15
0.05
0.2
0.4
0.05
1.0050

51 &Asteriskpseud;
Ho
0.75
2.0
0.15
0.05
0.2
0.4
0.05
1.0050

52 &Asteriskpseud;
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.05
0.960

53
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.05
0.970

54
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.05
1.0070

55
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.05
1.030

56 &Asteriskpseud;
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.05
1.040

[0011]

3

TABLE 1-3

Dielectric Composition (mol %)

Rare-earth

Sample
(Re2O3)

Total

Ba/Ti

Number
Element
Content
MgO
Mn2O3
V2O5
Cr2O3
Content
WO3
Ratio

57 &Asteriskpseud;
Ho
0.75
0.4
0.02

0.02
0.05
1.0050

58 &Asteriskpseud;
Ho
0.75
0.4

0.02

0.02
0.05
1.0050

59 &Asteriskpseud;
Ho
0.75
0.4

0.02
0.02
0.05
1.0050

60
Ho
0.75
0.4
0.03

0.03
0.05
1.0050

61
Ho
0.75
0.4

0.03

0.03
0.05
1.0050

62
Ho
0.75
0.4

0.03
0.03
0.05
1.0050

63
Ho
0.75
0.4
0.01
0.02

0.03
0.05
1.0050

64
Ho
0.75
0.4
0.05
0.02

0.07
0.05
1.0050

65
Ho
0.75
0.4
0.05

0.2
0.25
0.05
1.0050

66
Ho
0.75
0.4
0.05
0.01
0.2
0.26
0.05
1.0050

67
Ho
0.75
0.4
0.05
0.05
0.2
0.3
0.05
1.0050

68
Ho
0.75
0.4
0.2
0.2
0.2
0.6
0.05
1.0050

69
Ho
0.75
0.4
0.6

0.6
0.05
1.0050

70
Ho
0.75
0.4

0.6

0.6
0.05
1.0050

71
Ho
0.75
0.4

0.6
0.6
0.05
1.0050

72 &Asteriskpseud;
Ho
0.75
0.4
0.7

0.7
0.05
1.0050

73 &Asteriskpseud;
Ho
0.75
0.4

0.7

0.7
0.05
1.0050

74 &Asteriskpseud;
Ho
0.75
0.4

0.7
0.7
0.05
1.0050

75
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0
1.0050

76
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0.025
1.0050

77
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0.05
1.0050

78
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0.1
1.0050

79
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0.2
1.0050

80
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0.3
1.0050

81 &Asteriskpseud;
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0.4
1.0050

82
Ho
0.75
0.4
0.025
0.05
0.2
0.275
0.05
1.0050

83 &Asteriskpseud;
Ho
0.00
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

84
Ho
0.25
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

85
Ho
0.5
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

[0012]

4

TABLE 1-4

Dielectric Composition (mol %)

Rare-earth

Sample
(Re2O3)

Total

Ba/Ti

Number
Element
Content
MgO
Mn2O3
V2O5
Cr2O3
Content
WO3
Ratio

86
Ho
1.0
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

87
Ho
1.5
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

88 &Asteriskpseud;
Ho
2.0
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

89 &Asteriskpseud;
Ho
4.0
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

90
Sm
0.25
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

91
Sm
0.75
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

92
Eu
0.75
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

93
Gd
0.75
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

94
Tb
0.75
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

95
Dy
0.75
0.6
0.15
0.05
0.2
0.4
0.05
1.0050

96
Er
0.75
0.3
0.15
0.05
0.2
0.4
0.05
1.0050

97
Tm
0.75
0.3
0.15
0.05
0.2
0.4
0.05
1.0050

98
Yb
0.75
0.3
0.15
0.05
0.2
0.4
0.05
1.0050

99
Yb
1.0
0.3
0.15
0.05
0.2
0.4
0.05
1.0050

100
Y
1.0
0.3
0.15
0.05
0.2
0.4
0.05
1.0050

101
Ho/Dy
0.5/0.5
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

102
Ho/Dy/Yb
0.5/0.5/o.5
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

103
Sm/Ho/Yb
0.2/0.5/0.1
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

104
Sm/Yb
0.5/1.0
0.4
0.15
0.05
0.2
0.4
0.05
1.0050

105 &Asteriskpseud;
Ho
0.75
0
0.15
0.05
0.2
0.4
0.05
1.0050

106
Ho
0.75
0.2
0.15
0.05
0.2
0.4
0.05
1.0050

107
Ho
0.75
1.5
0.15
0.05
0.2
0.4
0.05
1.0050

108 &Asteriskpseud;
Ho
0.75
2.0
0.15
0.05
0.2
0.4
0.05
1.0050

109 &Asteriskpseud;
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.05
0.960

110
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.05
0.970

111
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.05
1.0070

112
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.05
1.030

113 &Asteriskpseud;
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.05
1.040

[0013]

5

TABLE 1-5

Dielectric Composition (mol %)

Rare-earth

Sample
(Re2O3)

Total

Total
Ba/Ti

Number
Element
Content
MgO
Mn2O3
V2O5
Cr2O3
Content
MoO3
WO3
Content
Ratio

114 &Asteriskpseud;
Ho
0.75
0.4
0.02

0.02
0.025
0.025
0.05
1.0050

115 &Asteriskpseud;
Ho
0.75
0.4

0.02

0.02
0.025
0.025
0.05
1.0050

116 &Asteriskpseud;
Ho
0.75
0.4

0.02
0.02
0.025
0.025
0.05
1.0050

117
Ho
0.75
0.4
0.03

0.03
0.025
0.025
0.05
1.0050

118
Ho
0.75
0.4

0.03

0.03
0.025
0.025
0.05
1.0050

119
Ho
0.75
0.4

0.03
0.03
0.025
0.025
0.05
1.0050

120
Ho
0.75
0.4
0.01
0.02

0.03
0.025
0.025
0.05
1.0050

121
Ho
0.75
0.4
0.05
0.02

0.07
0.025
0.025
0.05
1.0050

122
Ho
0.75
0.4
0.05

0.2
0.25
0.025
0.025
0.05
1.0050

123
Ho
0.75
0.4
0.05
0.01
0.2
0.26
0.025
0.025
0.05
1.0050

124
Ho
0.75
0.4
0.05
0.05
0.2
0.3
0.025
0.025
0.05
1.0050

125
Ho
0.75
0.4
0.2
0.2
0.2
0.6
0.025
0.025
0.05
1.0050

126
Ho
0.75
0.4
0.6

0.6
0.025
0.025
0.05
1.0050

127
Ho
0.75
0.4

0.6

0.6
0.025
0.025
0.05
1.0050

128
Ho
0.75
0.4

0.6
0.6
0.025
0.025
0.05
1.0050

129 &Asteriskpseud;
Ho
0.75
0.4
0.7

0.7
0.025
0.025
0.05
1.0050

130 &Asteriskpseud;
Ho
0.75
0.4

0.7

0.7
0.025
0.025
0.05
1.0050

131 &Asteriskpseud;
Ho
0.75
0.4

0.7
0.7
0.025
0.025
0.05
1.0050

132
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0
0
0
1.0050

133
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0.0125
0.0125
0.025
1.0050

134
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0.05
0.05
0.1
1.0050

135
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0.1
0.1
0.2
1.0050

136
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0.15
0.15
0.3
1.0050

137 &Asteriskpseud;
Ho
0.75
0.4
0.05
0.1
0.1
0.25
0.2
0.2
0.4
1.0050

138
Ho
0.75
0.4
C.025
0.05
0.2
0.275
0.025
0.025
0.05
1.0050

139 &Asteriskpseud;
Ho
0.00
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

140
Ho
0.25
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

141
Ho
0.5
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

142
Ho
1.0
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

[0014]

6

TABLE 1-6

Dielectric Composition (mol %)

Rare-earth

Sample
(Re2O3)

Total

Total
Ba/Ti

Number
Element
Content
MgO
Mn2O3
V2O5
Cr2O3
Content
MoO3
WO3
Content
Ratio

143
Ho
1.5
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

144 &Asteriskpseud;
Ho
2.0
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

145 &Asteriskpseud;
Ho
4.0
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

146
Sm
0.25
0.6
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

147
Sm
0.75
0.6
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

148
Eu
0.75
0.6
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

149
Gd
0.75
0.6
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

150
Tb
0.75
0.6
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

151
Dy
0.75
0.6
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

152
Er
0.75
0.3
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

153
Tm
0.75
0.3
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

154
Yb
0.75
0.3
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

155
Yb
1.0
0.3
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

156
Y
1.0
0.3
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

157
Ho/Dy
0.5/0.5
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

158
Ho/Dy/Yb
0.5/0.5/o.5
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

159
Sm/Ho/Yb
0.2/0.5/0.1
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

160
Sm/Yb
0.5/1.0
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

161 &Asteriskpseud;
Ho
0.75
0
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

162
Ho
0.75
0.2
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

163
Ho
0.75
1.5
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

164 &Asteriskpseud;
Ho
0.75
2.0
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0050

165 &Asteriskpseud;
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
0.960

166
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
0.970

167
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.0070

168
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.030

169 &Asteriskpseud;
Ho
0.75
0.4
0.15
0.05
0.2
0.4
0.025
0.025
0.05
1.040

[0015] Thereafter, the dried ceramic slurry was ground and then calcined in air at about 800° C. for 6 hours. The calcined slurry was then disaggregated by a wet method in a ball mill added with ethanol for 6 hours. Next, the disaggregated ceramic slurry was dried by being heated at about 150° C. for 6 hours, thereby obtaining the powder of the calcined ceramic slurry.

[0016] In a following step, a dielectric ceramic slurry was obtained by mixing and grinding 1000 g (100 parts by weight) of the powder of the dielectric ceramic slurry, 15 wt % of an organic binder and 50 wt % of water in a ball mill, wherein the organic binder includes acrylic ester polymer, glycerin, and a solution of condensed phosphate.

[0017] Next, the dielectric slurry was subjected to a vacuum air separator to remove air bubbles therefrom and formed into a thin film coated on a polyester film by using a reverse roll coater. Thus produced ceramic thin film on the polyester film was heated and dried at about 100° C., and then diced to thereby obtain square ceramic green sheets having a thickness of about 5 μm and a size of about 10 cm×10 cm.

[0018] Meanwhile, 0.9 g of ethyl cellulose dissolved in 9.1 g of butyl carbitol and 10 g of Nickel powder having an average diameter of about 0.5 μm were loaded and stirred in a stirrer for 10 hours to form a conductive paste for use in forming internal electrodes of ceramic capacitor. Thereafter, the conductive paste was printed on the prepared ceramic green sheets to form conductive patterns thereon and then the printed conductive paste was dried.

[0019] Subsequently, ten ceramic green sheets having the conductive patterns thereon were stacked against each other with the conductive patterns facing upward, thereby forming a laminated body. Every two neighboring sheets were disposed in such a manner that the conductive patterns provided thereon were shifted by one half of a pattern size along the length direction. The laminated body also included one or more ceramic dummy sheets stacked against each of the uppermost and the lowermost ceramic green sheets having conductive patterns thereon, the ceramic dummy sheets representing ceramic green sheets without having conductive patterns thereon.

[0020] Next, the laminated body was pressed with a load of about 40 tons at about 50° C. along the stacking direction of the ceramic sheets in the laminated body. Afterwards, the pressed laminated body was diced into a multiplicity of chip shaped ceramic bodies having a size of about 3.2 mm×1.6 mm.

[0021] Thereafter, Ni external electrodes were formed at two opposite sides of each respective chip shaped ceramic body by, e.g., a dipping method, one end portion of each of the internal electrodes being exposed to one of the two opposite sides of each chip shaped ceramic body. Then, the chip shaped ceramic bodies were loaded into a furnace capable of controlling an atmosphere therein and the organic binder contained in the loaded ceramic bodies was removed by heating the furnace in an N2 atmosphere. Then, the binder-removed chip shaped ceramic bodies were sintered at about 1300° C. in a non-oxidative atmosphere with oxygen partial pressure being in 10−5 to 10−10 atm order range. Thereafter, the sintered chip-shaped ceramic bodies were re-oxidized in an oxidative atmosphere to thereby obtain multilayer ceramic capacitors as shown in the drawing wherein reference numerals 10, 12 and 14 represent dielectric layers, internal electrodes and external electrodes, respectively.

[0022] Tables 2-1 to 2-6 exhibit a measurement result of electrical characteristics obtained from the thus produced multilayer ceramic capacitors, wherein a thickness of each dielectric layer incorporated in the capacitors was about 3 μm.

[0023] The electrical characteristics of the multilayer ceramic capacitors were obtained as follows.

[0024] (A) Relative permittivity (or dielectric constant) εs was computed based on a facing area of a pair of neighboring internal electrodes, a thickness of a dielectric layer positioned between the pair of neighboring internal electrodes, and the capacitance of a multilayer ceramic capacitor obtained under the condition of applying at 20° C. a voltage of 1.0 V (root mean square value) with a frequency of 1 kHz.

[0025] (B) Dielectric loss tan δ (%) was obtained under the same condition as established for measuring the permittivity cited above.

[0026] (C) Resistivity (Ω cm) was acquired by measuring a resistance between a pair of external electrodes after DC 25 V was applied for 60 seconds at 20° C. The number following “E” in the notation of a resistivity value presented in the accompanying Tables 2-1 to 2-6 represents an order. For instance, 2.5 E+12 represents 2.5×1012.

[0027] (D) Accelerated life (second) was obtained by measuring time period until an insulation resistivity (ρ) becomes 1×1010 Ω cm in a DC electric field of 20 V/μm at a temperature of 150° C.

[0028] (E) Capacitance variation Δ C/C25 (%) was obtained by measuring capacitances at −55° C., +25° C. and +125° C. in a thermostatic (or constant temperature) oven under the condition of applying a voltage of 1 V (rms value) with a frequency of 1 KHz, wherein C25 represents a capacitance at 25° C. and Δ C represents the difference between C25 and a capacitance measured at −55° C. to 125° C.

7TABLE 2-1ResistivityCapacitanceSintering(Ω cm)VariationAcceleratedSampleTemperatureat RoomΔC/C25 (%)LifeNumber(° C.)PermittivityTanδ (%)Temperature−55° C.125° C.(sec) 1&Asteriskpseud;130037803.32.5E + 12−13.4−14.945,800 2&Asteriskpseud;130038603.26.7E + 12−14.6−14.3165,800 3&Asteriskpseud;130038503.72.0E + 12−14.8−15870 4130037903.04.5E + 12−14−14.9287,900 5130035302.96.9E + 12−13.4−14.6875,900 6130036803.48.1E + 11−13.3−14.4458,900 7130037903.49.4E + 11−12.5−14.7678,940 8130038903.35.3E + 12−13.9−13.5897,500 9130038503.47.4E + 12−14.5−14.3658,90010130038703.54.6E + 12−14.5−14.9764,90011130037503.45.6E + 12−14.4−14.5759,80012130038903.22.2E + 129−14.6983,45013130035903.05.9E + 12−12.9−14.9398,50014130037403.09.5E + 11−14.5−14.5875,93015130036403.48.8E + 12−14.5−14.1754,90016&Asteriskpseud;130033003.12.5E + 12−13.5−13.4987,50017&Asteriskpseud;130031803.04.9E + 12−12.4−13.51,496,00018&Asteriskpseud;130034803.47.6E + 12−13−14.9289,54019130038703.44.3E + 12−14.4−14.8243,90020130036703.44.7E + 13−13.4−14.4456,70021130038903.55.3E + 12−14.9−14.61,489,00022130037803.51.0E + 13−14.5−152,985,00023130036803.12.0E + 13−13.9−14.51,894,50024&Asteriskpseud;130036503.84.4E + 11−14.6−3.519,80025130038503.48.4E + 13−14.5−14.9598,70026&Asteriskpseud;130059809.48.5E + 12−14.5−25.239027130035603.55.6E + 12−14.5−14.6578,90028130038503.51.2E + 12−14.5−15459,68029130035003.49.5E + 12−14.5−14.61,098,700

[0029]

8

TABLE 2-2

Resistivity
Capacitance

Sintering

(Ωcm)
Variation
Accelerated

Sample
Temperature

at Room
ΔC/C25 (%)
Life

Number
(° C.)
Permittivity
Tanδ (%)
Temperature
−55° C.
125° C.
(sec)

30
1300
3690
3.5
8.6E + 12
−14.6
−15
476,900

31&Asteriskpseud;
1300
Incapable of obtaining a sintered ceramic with high density

32&Asteriskpseud;
1300
Incapable of obtaining a sintered ceramic with high density

33
1300
3780
3.5
1.4E + 12
−14.5
−14.6
475,980

34
1300
3690
3.4
4.6E + 12
−14.5
−14.8
389,500

35
1300
3890
3.5
2.5E + 12
−14.4
−14.9
389,700

36
1300
3650
3.5
1.4E + 12
−13.8
−13.4
498,030

37
1300
3780
3.4
8.4E + 12
−15
−13.3
274,900

38
1300
3890
3.3
3.5E + 12
−14.5
−15
367,800

39
1300
3840
3.5
1.0E + 12
−14.3
−14.5
389,500

40
1300
3510
3.5
1.8E + 12
−14.5
−15
398,000

41
1300
3670
3.1
6.5E + 12
−14.5
−14.5
489,700

42
1300
3790
3.0
4.6E + 12
−14.6
−14.6
354,700

43
1300
3890
3.5
5.7E + 11
−14.5
−14.5
897,600

44
1300
3890
3.3
5.5E + 12
−14.4
−14.9
456,900

45
1300
4020
3.5
1.0E + 11
−14.5
−15
498,700

46
1300
3790
3.5
5.5E + 12
−14.1
−14.5
569,000

47
1300
3580
3.3
1.4E + 12
−14.5
−14.5
328,800

48&Asteriskpseud;
1300
7960
14.4
2.6E + 11
−35.9
−1.4
760

49
1300
3890
3.5
4.1E + 12
−14.5
−14.6
289,700

50
1300
3870
2.6
1.6E + 12
−13.5
−14.1
240,040

51&Asteriskpseud;
1300
2340
3.5
1.4E + 12
−13.9
−16.7
480

52&Asteriskpseud;
1300
Incapable of obtaining a sintered ceramic with high density

53
1300
3690
3.5
2.1E + 13
−14.6
−14.9
348,990

54
1300
3650
3.3
4.4E + 13
−14.5
−14.5
387,500

55
1300
3790
3.5
4.1E + 13
−14.5
−14.7
365,900

56&Asteriskpseud;
1300
3080
3.1
4.9E + 13
−14.5
−14.5
4,800

[0030]

9

TABLE 2-3

Resistivity
Capacitance

Sintering

(Ω cm)
Variation
Accelerated

Sample
Temperature

at Room
ΔC/C25 (%)
Life

Number
(° C.)
Permittivity
Tanδ (%)
Temperature
−55° C.
125° C.
(sec)

57&Asteriskpseud;
1300
3850
3.3
8.3E + 12
−14.1
−14.9
147,500

58&Asteriskpseud;
1300
3740
3.4
7.7E + 12
−14.8
−14.2
165,900

59&Asteriskpseud;
1300
3920
3.9
5.2E + 12
−14.6
−14.3
63,200

60
1300
3820
3.3
4.8E + 12
−14.2
−14.6
274,500

61
1300
3790
3.2
3.8E + 12
−14.5
−13.9
636,400

62
1300
3810
3.4
1.6E + 12
−14.3
−13.7
503,500

63
1300
3840
3.2
7.4E + 12
−13.4
−14.8
462,800

64
1300
3860
3.1
8.3E + 12
−14.1
−14.4
587,700

65
1300
3710
3.3
3.3E + 12
−13.7
−14.8
1,376,200

66
1300
3830
3.5
8.1E + 11
−13.9
−14.1
739,900

67
1300
3720
3.1
7.3E + 12
−13.8
−14.5
356,200

68
1300
3620
3.3
5.5E + 12
−14.2
−13.2
478,300

69
1300
3530
3.4
2.9E + 12
−13.7
−14.6
368,400

70
1300
3620
3.4
8.2E + 12
−13.6
−13.9
635,800

71
1300
3580
3.4
6.1E + 12
−14.3
−14.2
739,200

72&Asteriskpseud;
1300
3460
3.0
6.4E + 12
−14.8
−14.0
642,300

73&Asteriskpseud;
1300
3340
2.8
8.2E + 12
−14.2
−13.6
1,738,500

74&Asteriskpseud;
1300
3410
3.4
4.5E + 12
−14.5
−12.5
350,600

75
1300
3780
3.3
7.3E + 12
−14.1
−13.9
227,500

76
1300
3850
3.4
2.7E + 12
−13.8
−14.6
468,300

77
1300
3820
3.1
6.6E + 12
−14.3
−13.6
1,045,600

78
1300
3840
3.2
3.1E + 13
−14.6
−13.7
1,736,500

79
1300
3770
3.4
1.1E + 13
−14.7
−14.4
1,056,200

80
1300
3640
3.5
4.0E + 13
−13.9
−14.9
943,600

81&Asteriskpseud;
1300
3660
3.5
4.4E + 12
−14.8
−13.2
163,600

82
1300
3590
3.4
8.4E + 13
−14.5
−14.9
598,700

83&Asteriskpseud;
1300
3660
4.8
8.5E + 12
−12.8
−18.6
1,700

84
1300
3850
3.5
5.6E + 12
−14.5
−14.6
365,200

85
1300
3740
3.5
1.2E + 12
−14.5
−15
573,800

[0031]

10

TABLE 2-4

Resistivity
Capacitance

Sintering

(Ω cm)
Variation
Accelerated

Sample
Temperature

at Room
ΔC/C25 (%)
Life

Number
(° C.)
Permittivity
Tanδ (%)
Temperature
−55° C.
125° C.
(sec)

86
1300
3850
3.4
9.5E + 12
−14.5
−14.6
356,200

87
1300
3760
3.5
8.6E + 12
−14.6
−15
104,300

88&Asteriskpseud;
1300
Incapable of obtaining a sintered ceramic with high density

89&Asteriskpseud;
1300
Incapable of obtaining a sintered ceramic with high density

90
1300
3880
3.4
4.8E + 12
−14.6
−13.7
437,200

91
1300
3690
3.1
7.6E + 12
−13.8
−14.8
747,800

92
1300
3650
3.4
3.6E + 12
−14.3
−14.2
457,600

93
1300
3710
3.4
3.7E + 12
−14.2
−14.2
235,600

94
1300
3770
3.3
9.5E + 11
−14.2
−14.5
460,400

95
1300
3690
3.2
8.4E + 12
−13.5
−14.8
467,500

96
1300
3730
3.3
2.6E + 12
−14.5
−14.2
845,600

97
1300
3810
3.2
4.4E + 12
−14.2
−14.8
873,500

98
1300
3830
3.5
7.3E + 12
−13.8
−14.3
630,100

99
1300
3690
3.2
3.3E + 12
−14.1
−14.3
264,600

100
1300
3780
3.3
8.6E + 11
−14.8
−14.9
358,300

101
1300
3850
3.4
5.1E + 12
−14.5
−14.2
356,900

102
1300
3920
3.2
3.0E + 12
−13.9
−14.4
704,800

103
1300
3660
3.4
7.7E + 12
−14.6
−13.8
569,400

104
1300
3830
3.2
8.3E + 12
−14.7
−13.6
479,600

105&Asteriskpseud;
1300
4890
28.8
8.1E + 10
−36.2
1.7
26,300

106
1300
3650
3.4
5.9E + 12
−14.4
−13.6
264,800

107
1300
3520
2.9
2.9E + 12
−14.3
−14.2
326,900

108&Asteriskpseud;
1300
3440
2.5
6.2E + 12
−13.8
−14.8
105,600

109&Asteriskpseud;
1300
Incapable of obtaining a sintered ceramic with high density

110
1300
3850
3.4
4.2E + 12
−14.2
−13.7
365,200

111
1300
3740
3.5
8.9E + 12
−14.7
−13.9
303,500

112
1300
3640
3.4
7.6E + 12
−14.3
−14.2
402,800

113&Asteriskpseud;
1300
3310
3.2
6.9E + 12
−14.8
−14.4
62,300

[0032]

11

TABLE 2-5

Resistivity
Capacitance

Sintering

(Ω cm)
Variation
Accelerated

Sample
Temperature

at Room
ΔC/C25 (%)
Life

Number
(° C.)
Permittivity
Tanδ (%)
Temperature
−55° C.
125° C.
(sec)

114&Asteriskpseud;
1300
3690
3.4
5.4E + 12
−13.5
−14.8
44,300

115&Asteriskpseud;
1300
3970
3.4
7.8E + 12
−14.7
−14.4
179,200

116&Asteriskpseud;
1300
3940
3.6
8.4E + 12
−14.7
−14.9
1,430

117
1300
3810
3.2
7.3E + 12
−14.3
−15
312,900

118
1300
3540
3.1
7.8E + 12
−13.6
−14.9
726,700

119
1300
3590
3.4
2.2E + 11
−13.6
−14.5
503,800

120
1300
3740
3.5
7.1E + 11
−12.3
−14.4
907,500

121
1300
3620
3.2
4.9E + 12
−13.7
−13.6
930,200

122
1300
3720
3.4
8.2E + 12
−14.7
−14.5
754,900

123
1300
3530
3.4
5.5E + 12
−14.6
−15
880,300

124
1300
3640
3.4
4.1E + 12
−14.3
−14.4
699,800

125
1300
3880
3.3
3.4E + 12
7.2
−14.6
856,700

126
1300
3510
3.1
7.3E + 12
−13.2
−14.7
324,800

127
1300
3680
3.1
1.3E + 11
−14.6
−14.3
994,000

128
1300
3550
3.4
7.5E + 12
−14.7
−14
887,500

129&Asteriskpseud;
1300
3420
3.1
2.5E + 12
−13.5
−13.4
987,500

130&Asteriskpseud;
1300
3210
3.1
5.8E + 12
−12.6
−13.7
1,296,700

131&Asteriskpseud;
1300
3390
3.5
4.3E + 12
−13.3
−14.8
230,900

132
1300
3790
3.4
6.4E + 12
−14.5
−14.7
239,400

133
1300
3570
3.5
3.7E + 13
−13.7
−14.2
645,500

134
1300
3780
3.4
4.9E + 12
−14.8
−14.7
1,396,700

135
1300
3610
3.5
8.9E + 12
−14.6
−14.8
3,005,800

136
1300
3640
3.3
4.5E + 13
−13.8
−14.6
1,674,700

137&Asteriskpseud;
1300
3520
3.9
5.8E + 11
−14.7
−4.3
21,000

138
1300
3790
3.5
7.7E + 13
−14.6
−14.8
663,800

139&Asteriskpseud;
1300
6030
8.9
7.6E + 12
−14.1
−29.3
1,290

140
1300
3580
3.5
7.4E + 12
−14.6
−14.5
703,700

141
1300
3920
3.5
4.5E + 12
−14.6
−14.8
553,200

142
1300
3630
3.4
7.3E + 12
−14.6
−14.7
1,329,700

[0033]

12

TABLE 2-6

Resistivity
Capacitance

Sintering

(Ω cm)
Variation
Accelerated

Sample
Temperature

at Room
ΔC/C25 (%)
Life

Number
(° C.)
Permittivity
Tanδ (%)
Temperature
−55° C.
125° C.
(sec)

143
1320
3740
3.5
7.8E + 12
−14.9
−14.7
664,800

144&Asteriskpseud;
1320
Incapable of obtaining a sintered ceramic with high density

145&Asteriskpseud;
1320
Incapable of obtaining a sintered ceramic with high density

146
1320
3840
3.5
4.3E + 12
−14.6
−14.9
507,400

147
1320
3710
3.4
5.3E + 12
−14.8
−14.7
408,300

148
1320
4010
3.5
3.5E + 12
−14.5
−14.6
498,300

149
1320
3740
3.5
2.8E + 12
−13.9
−13.3
520,800

150
1320
3690
3.4
7.5E + 12
−14.9
−13.1
372,500

151
1320
3930
3.5
4.2E + 12
−14.7
−14.8
479,800

152
1320
3900
3.5
3.2E + 12
−14.5
−14.7
378,200

153
1320
3660
3.5
5.3E + 12
−14.6
−14.9
378,200

154
1320
3720
3.2
4.3E + 12
−14.7
−14.4
593,700

155
1320
3800
3.1
5.8E + 12
−14.6
−14.8
339,700

156
1320
3920
3.5
6.6E + 11
−14.4
−14.6
945,700

157
1320
3920
3.4
4.5E + 12
−14.2
−14.8
519,800

158
1320
3890
3.4
3.6E + 11
−14.6
−14.9
504,900

159
1320
3590
3.3
9.8E + 12
−13.9
−14.7
554,300

160
1320
3640
3.4
4.3E + 12
−14.4
−14.5
387,400

161&Asteriskpseud;
1320
8030
11.4
7.2E + 11
−40.5
0.4
1,200

162
1320
3770
3.5
4.0E + 12
−14.6
−14.5
337,200

163
1320
3730
2.7
3.5E + 12
−13.7
−14.3
293,600

164&Asteriskpseud;
1320
2490
3.6
6.6E + 12
−13.8
−16.5
1,600

165&Asteriskpseud;
1320
Incapable of obtaining a sintered ceramic with high density

166
1320
3740
3.4
7.5E + 13
−14.7
−15
447,300

167
1320
3740
3.4
5.6E + 13
−14.7
−14.6
406,500

168
1320
3650
3.5
3.8E + 13
−14.4
−14.6
350,700

169&Asteriskpseud;
1320
3120
3.2
6.9E + 13
−14.5
−14.2
79,500

[0034] As clearly seen from Tables 1-1 to 1-6 and Tables 2-1 to 2-6, multilayer ceramic capacitors with highly improved reliability having relative permittivity εs equal to or greater than 3500, capacitance variation Δ C/C25 within the range from −15% to +15% at temperatures ranging from −55° C. to +125° C., tan δ of 3.5% or less and accelerated life of 200,000 seconds or greater could be obtained from samples sintered in a non-oxidative atmosphere even at a temperature of 1300° C. or lower in accordance with the present invention.

[0035] However, samples 1 to 3, 16 to 18, 24, 26, 31, 32, 48, 51, 52, 56 to 59, 72 to 74, 81, 83, 88, 89, 105, 108, 109, 113 to 116, 129 to 131, 137, 139, 144, 145, 161, 164, 165 and 169 (marked with “” at the column of sample number in Tables) could not satisfy the above-specified electrical characteristics. Therefore, it appears that such samples fall outside a preferable compositional range of the present invention.

[0036] The reasons why the preferable compositional range for dielectric ceramics for use in forming dielectric layers of the multilayer ceramic capacitor in accordance with the present invention should be limited to certain values will now be described. In Tables 1-1 to 1-6, the amount of oxides of Ba and Ti was 100 mol % in terms of BaTiO3 (i.e., assuming Ba and Ti are in the form of BaTiO3).

[0037] First, when the content of an oxide of a rare-earth element represented by Re (Re is selected, e.g., from the group consisting of Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Y) is 0 mol % in terms of Re2O3 (i.e., assuming the oxide of Re is in the form of Re2O3 as in the samples 26, 83 and 139, the capacitance variation Δ C/C25 of a produced multilayer ceramic capacitor goes beyond the range from −15% to +15% when temperature varies from −55° C. to +125° C. and a desired accelerated life may not be attained; whereas when the oxide of Re is set to be 0.25 mol % in terms of Re2O3 as in samples 27, 84 and 140, the desired electrical characteristics can be successfully obtained.

[0038] Further, when the content of the oxide of the rare-earth element Re is equal to or greater than 2.0 mol % in terms of Re2O3 as in the samples 31, 32, 88, 89,144 and 145, highly densified ceramic bodies with a highly enhanced density may not be obtained by the sintering at 1300° C.; whereas when the oxide of the rare-earth element Re is set to be 1.5 mol % in terms of Re2O3 as in the samples 30, 87 and 143, the desired electrical characteristics can be successfully obtained.

[0039] Accordingly, the preferable range of the total content of the oxide of rare-earth element Re is from 0.25 to 1.5 mol % in terms of Re2O3.

[0040] It is noted that same effects can be produced regardless of whether a single rare-earth element is used or two or more of rare-earth elements are used together as long as the above-described preferable content range of the rare-earth element Re is satisfied.

[0041] When the content of an oxide of Mg is 0 mol % in terms of MgO, as in the samples 48, 105 and 161, the capacitance variation Δ C/C25 of the produced multilayer ceramic capacitors may exceed the range from −15% to +15% when the temperature varies from −55° C. to +125° C. and the desired accelerated life may not be obtained; whereas when the content of the oxide of Mg is set to be 0.2 mol % in terms of MgO as in samples 49, 106 and 162, the desired electrical characteristics can be successfully obtained.

[0042] In addition, when the content of the oxide of Mg is 2.0 mol % in terms of MgO as in the samples 51, 108 and 164, the relative permittivity of the produced multilayer ceramic capacitors may become equal to or less than 3500 and the desired accelerated life can not be obtained. Further, the capacitance variation Δ C/C25 sometimes may go beyond the range of −15% to +15% when the temperature varies from −55° C. to 125° C. However, when the content of the oxide of Mg is set to be 1.5 mol % in terms of MgO as in samples 50, 107 and 163, the desired electrical characteristics can be successfully obtained.

[0043] Accordingly, the content of the oxide of Mg optimally ranges from 0.2 to 1.5 mol % in terms of MgO.

[0044] When the content of an oxide of Mn, V or Cr is 0.02 mol % in terms of Mn2O3, V2O5 or Cr2O3 as in the samples 1 to 3, 57 to 59 and 114 to 116, the desired accelerated life of the produced multilayer ceramic capacitors may not be obtained; whereas when the content of sum of the oxides of Mn, V and Cr is set to be 0.03 mol % in terms of Mn2O3, V2O5 and Cr2O3 as in the samples 4 to 7, 60 to 63 and 117 to 120, the desired electrical characteristics can be successfully obtained.

[0045] Further, when the content of an oxide of the Mn, V, or Cr is 0.7 mol % in terms of Mn2O3, V2O5 or Cr2O3 as in the samples 16 to 18, 72 to 74 and 129 to 131, the relative permittivity of the produced capacitors becomes equal to or less than 3500. However, when the total content of oxides of Mn, V and Cr is set to be 0.6 mol % in terms of Mn2O3, V2O5 and Cr2O3 as in samples 12 to 15, 68 to 71 and 125 to 128, the desired electrical characteristics can be successfully obtained.

[0046] Accordingly, it is preferable that the total amount of the oxides of Mn, V and Cr ranges from 0.03 to 0.6 mol % in terms of Mn2O3, V2O5 and Cr2O3.

[0047] Further, it is to be noted that same effects can be obtained regardless of whether an oxide of one of the elements Mn, V and Cr is used or two or more thereof are used together as long as the total content thereof satisfies the above specified range, as in the samples 4 to 15, 60 to 71 and 117 to 128.

[0048] When the total content of the oxides of Mo and W is 0.4 mol % in terms of MoO3 and WO3 as in the samples 24, 81 and 137, tan δ of the produced capacitors becomes equal to or greater than 3.5 and the desired accelerated life thereof cannot be obtained. However, if the total content of oxides of Mo and W is set to be 0.3 mol % in terms of MoO3 and WO3, respectively, as in samples 23, 80 and 136, the desired electrical characteristics can be successfully obtained.

[0049] Accordingly, it is preferable that the total content the oxides of Mo and W is between 0 and 0.3 mol % in terms of MoO3 and WO3.

[0050] Furthermore, same effects can be obtained regardless of whether the oxides of Mo and W are used separately as in the samples 20 to 23 and 76 to 80 or used together as in samples 133 to 136 as long as the total content thereof is maintained at or below 0.3 mol %.

[0051] It is more preferable that the total content of the oxides of Mo and W ranges from 0.025 to 0.3 mol % in terms of MoO3 and WO3 since the addition of Mo and/or W in that range gives rise to a further increased operation and reliability of a ceramic capacitor.

[0052] When the ratio of Ba/Ti is 0.960, as in the samples 52, 109 and 165, the sintering at 1300° C. can not produce highly densified ceramic bodies; whereas when the ratio of Ba/Ti is set to be 0.970 as in the samples 53, 110 and 166, the desired electrical characteristics can be successfully obtained.

[0053] Moreover, if the ratio of Ba/Ti is 1.040, as in the samples 56, 113 and 169, the desired accelerated life may not be obtained though tan δ of the produced capacitors becomes equal to or less than 3.5. However, when the ratio of Ba to Ti is set to be 1.030 as in samples 55, 112 and 168, the desired electrical characteristics can be successfully obtained.

[0054] Accordingly, the optimum ratio of Ba/Ti ranges from 0.970 and 1.030.

[0055] Further, Ca or Sr can be used instead of Ba for adjusting Ba/Ti ratio. That is, as long as the ratio of the sum of Ba, Ca and Sr to Ti. i.e., (Ba+Ca)/Ti ratio, (Ba+Sr)/Ti ratio or (Ba+Ca+Sr)/Ti satisfies the optimum range from 0.970 to 1.030, the desired characteristics can be obtained.

[0056] Still further, barium carbonate, barium acetate, barium nitrate, calcium acetate, strontium nitrate or the like can be used in controlling the ratio.

[0057] The present invention can produce a multilayer ceramic capacitor capable of providing a desired operating life with a highly improved reliability, wherein the capacitor exhibits a relative permittivity εs of 3500 or greater, tan δ of 3.5% or less and a capacitance variation Δ C/C25 ranging from −15% and +15% within the temperature range from −55° C. to +125° C.

[0058] Although the present invention has been described with reference to the multilayer ceramic capacitors in this specification, it will be apparent to those skilled in the art that the present invention is also applicable to single layer ceramic capacitors.

[0059] While the invention has been shown and described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.

Ceramic composition and ceramic capacitor

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