Ceramic capacitor and method for fabricating the same

Claim 1

A ceramic capacitor, comprising: at least one dielectric ceramic layer consisting essentially of a dielectric ceramic composition and at least two internal electrodes sandwiching said dielectric ceramic composition; and characterized by: said dielectric ceramic composition consisting essentially of a fired mixture of a basic component of 100 weight portions and an additional component in the range of 0.2 to 5 weight portions; said basic component consisting essentially of a material represented by the following formula: {(Ba 1-w-x Ca w Mg x )O} k (Ti 1-y-z Zr y R z )O 2-z/2 where, R is one or more elements selected from a group consisting of Sc, Y, Gd, Dy, Ho, Er, Yb, Tb, Tm and Lu; and w, x, y, z and k are numerals fulfilling the following conditions: 0.00 ≦ w ≦ 0.27 0.001 ≦ x ≦ 0.03 0.05 ≦ y ≦ 0.26 0.002 ≦ z ≦ 0.04 1.00 ≦ k ≦ 1.04 said additional component consisting essentially of Li₂O, SiO₂ and MO (wherein said MO is at least one oxide selected from a group consisting of BaO, SrO, CaO, MgO and ZnO); and a ratio among amounts of Li₂O, SiO₂ and MO in said additional component is within an area in a ternary system diagram, of mol % having five vertexes of first to fifth vertexes, wherein according to Fig. 2: said first vertex A represents a condition in which amounts of Li₂O is 1 mol %, SiO₂ is 80 mol % and MO is 19 mol %; said second vertex B represents a condition in which amounts of Li₂O is 1 mol %, SiO₂ is 39 mol % and MO is 60 mol %; said third vertex C represents a condition in which amounts of Li₂O is 30 mol %, SiO₂ is 30 mol % and MO is 40 mol %; said fourth vertex D represents a condition in which amounts of Li₂O is 50 mol %, SiO₂ is 50 mol % and MO is 0 mol %; and said fifth vertex E represents a condition in which amounts of Li₂O is 20 mol %, SiO₂ is 80 mol % and MO is 0 mol %.

Claim 4

A method for fabricating a ceramic capacitor, comprises the steps of: providing a mixture of non-sintered ceramic powder; forming a non-sintered ceramic sheet consisting of said mixture; fabricating a laminated structure in which said non-sintered ceramic sheet is sandwiched between at least two conductive paste layers; firing said laminated structure under a non-oxidative atmosphere; and heating said fired laminated structure under an oxidative atmosphere; characterized by: said mixture of non-sintered ceramic powder consisting essentially of a fired mixture of a basic component of 100 weight portions and an additional component in the range of 0.2 to 5 weight portions; said basic component consisting essentially of a material represented by the following formula: {(Ba 1-w-x Ca w Mg x )O} k (Ti 1-y-z Zr y R z )O 2-z/2 where, R is one or more elements selected from a group consisting of Sc, Y, Gd, Dy, Ho, Er, Yb, Tb, Tm and Lu; and w, x, y, z and k are numerals fulfilling the following conditions: 0.00 ≦ w ≦ 0.27 0.001 ≦ x ≦ 0.03 0.05 ≦ y ≦ 0.26 0.002 ≦ z ≦ 0.04 1.00 ≦ k ≦ 1.04 said additional component consisting essentially of Li₂O, SiO₂ and MO (wherein said MO is at least one oxide selected from a group consisting of BaO, SrO, CaO, MgO and ZnO) ; and a ratio among amounts of Li₂O, SiO₂ and MO in said additional component is within an area in a ternary system diagram of mol % having five vertexes of first to fifth vertexes, wherein according to Fig. 2: said first vertex A represents a condition in which amounts of Li₂O is 1 mol %, SiO₂ is 80 mol % and MO is 19 mol %; said second vertex B represents a condition in which amounts of Li₂O is 1 mol %, SiO₂ is 39 mol % and MO is 60 mol %; said third vertex C represents a condition in which amounts of Li₂O is 30 mol %, SiO₂ is 30 mol % and MO is 40 mol %; said fourth vertex D represents a condition in which amounts of Li₂O is 50 mol %, SiO₂ is 50 mol % and MO is 0 mol %; and said fifth vertex E represents a condition in which amounts of Li₂O is 20 mol %, SiO₂ is 80 mol % and MO is 0 mol %.

Claim 5

A method for fabricating a ceramic capacitor, comprises the steps of: providing a mixture of non-sintered ceramic powder; forming a non-sintered ceramic sheet consisting of said mixture; fabricating a laminated structure in which said non-sintered ceramic sheet is sandwiched between at least two conductive paste layers; firing said laminated structure under a non-oxidative atmosphere; and heating said fired laminated structure under an oxidative atmosphere; characterized by: said mixture of non-sintered ceramic powder consisting essentially of a fired mixture of a basic component of 100 weight portions and an additional component in the range of 0.2 to 5 weight portions; said basic component consisting essentially of a material represented by the following formula: {(Ba 1-w-x Ca w Mg x )O} k (Ti 1-y-z Zr y R z )O 2-z/2 where, R is one or more metal elements selected from a group consisting of Sc, Y, Gd, Dy, Ho, Er, Yb, Tb, Tm and Lu; and w, x, y, z and k are numerals fulfilling the following conditions: 0.00 ≦ w ≦ 0.27 0.001 ≦ x ≦ 0.03 0.05 ≦ y ≦ 0.26 0.002 ≦ z ≦ 0.04 1.00 ≦ k ≦ 1.04 said additional component consisting essentially of B₂O₃, SiO₂ and MO (wherein said MO is at least one oxide selected from a group consisting of BaO, SrO, CaO, MgO and ZnO); and a ratio among amounts of B₂O₃, SiO₂ and MO in said additional component is within an area in a ternary system diagram of mol % having six vertexes of first to sixth vertexes, wherein according to Fig. 3: said first vertex F represents a condition in which amounts of B₂O₃ is 1 mol %, SiO₂ is 80 mol % and MO is 19 mol %; said second vertex G represents a condition in which amounts of B₂O₃ is 1 mol %, SiO₂ is 39 mol % and MO is 60 mol %; said third vertex H represents a condition in which amounts of B₂O₃ is 30 mol %, SiO₂ is 0 mol % and MO is 70 mol %; said fourth vertex I represents a condition in which amounts of B₂O₃ is 90 mol %, SiO₂ is 0 mol % and MO is 10 mol %; said fifth vertex J represents a condition in which amounts of B₂O₃ is 90 mol %, SiO₂ is 10 mol % and MO is 0 mol %; and said sixth vertex K represents a condition in which amounts of B₂O₃ is 20 mol %, SiO₂ is 80 mol % and MO is 0 mol %.

Claim 6

A method for fabricating a ceramic capacitor, comprises the steps of: providing a mixture of non-sintered ceramic powder; forming a non-sintered ceramic sheet consisting of said mixture; fabricating a laminated structure in which said non-sintered ceramic sheet is sandwiched between at least two conductive paste layers; firing said laminated structure under a non-oxidative atmosphere; and heating said fired laminated structure under an oxidative atmosphere; characterized by: said mixture of non-sintered ceramic powder consisting essentially of a fired mixture of a basic component of 100 weight portions and an additional component in the range of 0.2 to 5 weight portions; said basic component consisting essentially of a material represented by the following formula: {(Ba 1-w-x Ca w Mg x )O} k (Ti 1-y-z Zr y R z )O 2-z/2 where, R is one or more metal elements selected from a group consisting of Sc, Y, Gd, Dy, Ho, Er, Yb, Tb, Tm and Lu ; and w, x, y, z and k are numerals fulfilling the following conditions: 0.00 ≦ w ≦ 0.27 0.001 ≦ x ≦ 0.03 0.05 ≦ y ≦ 0.26 0.002 ≦ z ≦ 0.04 1.00 ≦ k ≦ 1.04 said additional component consisting essentially of B₂O₃, SiO₂ and Li₂O; and a ratio among amounts of B₂O₃, SiO₂ and Li₂O in said additional component is within an area in a ternary system diagram of mol % having six vertexes of first to sixth vertexes, wherein according to Fig. 4: said first vertex L represents a condition in which amounts of B₂O₃ is 1 mol %, SiO₂ is 50 mol % and Li₂O is 49 mol %; said second vertex M represents a condition in which amounts of B₂O₃ is 50 mol %, SiO₂ is 1 mol % and Li₂O is 49 mol %; said third vertex N represents a condition in which amounts of B₂O₃ is 80 mol %, SiO₂ is 1 mol % and Li₂O is 19 mol %; said fourth vertex O represents a condition in which amounts of B₂O₃ is 89 mol %, SiO₂ is 10 mol % and Li₂O is 1 mol %; said fifth vertex P represents a condition in which amounts of B₂O₃ is 19 mol %, SiO₂ is 80 mol % and Li₂O is 1 mol %; and said sixth vertex Q represents a condition in which amounts of B₂O₃ is 1 mol %, SiO₂ is 80 mol % and Li₂O is 19 mol %.