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

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: (Bi 2 O 2 ) 2+ (A m−1 B m O 3m+1 ) 2− , or Bi 2 A m−1 B m O 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.

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: (Bi 2 O 2 ) 2+ (A m−1 B m O 3m+1 ) 2−  or Bi 2 A m−1 B m O 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, and when temperature is within temperature range of at least −55° C. to +150° C., average change rates (Δ ε) of dielectric constant of said composition is within ±20 ppm/° C. (25° C. reference temperature).    
   
   
       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: Bi 2 A m−1−x Re x B m O 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,    the bismuth layer-structured compound is expressed by a formula: (Bi 2 O 2 ) 2+ (A m−1 B m O 3m+1 ) 2−  or Bi 2 A m−1 B m O 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, and when temperature is within temperature range of at least −55° C. to +150° C., average change rates (Δ ε) of dielectric constant of said composition is within ±120 ppm/° C. (25° C. reference temperature).    
   
   
       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: Bi 2 A m−1−x Re x B m O 3m+3 , said x is 0.01 to 2.0.  
   
   
       10 . The thin-film capacitance device as in  claim 6 , wherein said substrate is composed of amorphous material.  
   
   
       11 . The thin-film capacitance device as in  claim 6 , wherein thickness of said dielectric thin-film is 5 to 1000 nm.  
   
   
       12 . 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.  
   
   
       13 . The thin-film capacitance device as in  claim 6 , wherein said lower electrode is formed by epitaxial growth on said substrate to [100] orientation.  
   
   
       14 . 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,    said bismuth layer-structured compound is expressed by a formula: (Bi 2 O 2 ) 2+ (A m−1 B m O 3m+1 ) 2−  or Bi 2 A m−1 B m O 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, and when temperature is within temperature range of at least −55° C. to +150° C., average change rates (Δ ε) of dielectric constant of said composition is within ±20 ppm/° C. (25° C. reference temperature).    
   
   
       15 . The thin-film multilayer capacitor as in  claim 14 , characterized in degree of c-axis orientation for said bismuth layer-structured compound is 80% or more.  
   
   
       16 . The thin-film multilayer capacitor as in  claim 14 , 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).  
   
   
       17 . The thin-film multilayer capacitor as in  claim 16 , wherein when said rare-earth element is “Re” and said bismuth layer-structured compound is expressed by formula: Bi 2 A m−1−x Re x B m O 3m+3 , said x is 0.01 to 2.0.  
   
   
       18 . The thin-film multilayer capacitor as in  claim 14 , characterized in said internal electrode thin-film is composed of noble metal, base metal or conductive oxide.  
   
   
       19 . The thin-film multilayer capacitor as in  claim 14 , wherein said substrate is composed of amorphous material.  
   
   
       20 . The thin-film multilayer capacitor as in  claim 14 , wherein thickness of said dielectric thin-film is 5 to 1000 nm.  
   
   
       21 . The thin-film multilayer capacitor as in  claim 14 , wherein “m” in the formula composing said bismuth layer-structured compound is any one of 2, 4, 6 and 8.  
   
   
       22 . The thin-film multilayer capacitor as in  claim 14 , wherein said internal electrode thin-film is formed to [100] orientation.  
   
   
       23 . 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: (Bi 2 O 2 ) 2+ (A m−1 B m O 3m+1 ) 2−  or Bi 2 A m−1 B m O 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, and when temperature is within temperature range of at least −55° C. to +150° C., average change rates (Δ ε) of dielectric constant of said composition is within ±120 ppm/° C. (25° C. reference temperature).    
   
   
       24 . The dielectric thin-film composition for capacitor as in  claim 23 , characterized in degree of c-axis orientation for said bismuth layer-structured compound is 80% or more.  
   
   
       25 . 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,    the bismuth layer-structured compound is expressed by a formula: (Bi 2 O 2 ) 2+ (A m−1 B m O 3m+1 ) 2−  or Bi 2 A m−1 B m O 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, and when temperature is within temperature range of at least −55° C. to +150° C., average change rates (Δ ε) of dielectric constant of said composition is within ±120 ppm/° C. (25° C. reference temperature).    
   
   
       26 . The thin-film capacitor as in  claim 25 , characterized in degree of c-axis orientation for said bismuth layer-structured compound is 80% or more.  
   
   
       27 . 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: (Bi 2 O 2 ) 2+ (A m−1 B m O 3m+1 ) 2−  or Bi 2 A m−1 B m O 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, and when temperature is within temperature range of at least −55° C. to +150° C., average change rates (Δ ε) of dielectric constant of said composition is within ±120 ppm/° C. (25° C. reference temperature).    
   
   
       28 . The high-dielectric constant insulating film as in  claim 27 , characterized in degree of c-axis orientation for said bismuth layer-structured compound is 80% or more.  
   
   
       29 . The high-dielectric constant insulating film as in  claim 27 , 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).  
   
   
       30 . The high-dielectric constant insulating film as in  claim 29 , wherein when said rare-earth element is “Re” and said bismuth layer-structured compound is expressed by formula: Bi 2 A m−1−x Re x B m O 3m+3 , said x is 0.01 to 2.0.