Patent ID: 6999302

Claim:
A multilayer ceramic capacitor having a multilayer structure in which dielectric layers and internal electrode layers are alternately stacked, wherein each of said dielectric layers comprises: a main component containing barium titanate; a first auxiliary component composed of at least one kind selected from the group consisting of MgO, CaO, BaO, and SrO; a second auxiliary component containing a silicon oxide as a main component; a third auxiliary component composed of at least one kind selected from the group consisting of V 2 O 5 , MoO 3 , and WO 3 ; a fourth auxiliary component composed of an oxide of at least one kind of first rare-earth element (R1) selected from the group consisting of Sc, Er, Tm, Yb, and Lu; a fifth auxiliary component composed of CaZrO 3 or a mixture (CaO+ZrO 2 ) of CaO and ZrO 2 ; and a sixth auxiliary component composed of an oxide of at least one kind of second rare-earth-element (R2) selected from the group consisting of Y, Dy, Ho, Tb, Gd, and Eu, wherein, assuming that, with respect to 100 mol of the main component containing barium titanate, the content (mol) of the first auxiliary component is given as y1, the content (mol) of the second auxiliary component is given as y2, the content (mol) of the third auxiliary component is given as y3, the content (mol) of the fourth auxiliary component is given as y4, the content (mol) of the fifth auxiliary component is given as y5, and the content (mol) of the sixth auxiliary component is given as y6, a value of y1 falls within the range of 0.1 to 3.0 mol, a value of y2 falls within the range of 2 to 10 mol, a value of y3 falls within the range of 0.01 to 0.5 mol, a value of y4 falls within the range of 0.5 to 7 mol (representing the content of R1 alone), a value of y5 falls within the range of 5 mol or less (not including zero), and a value of y6 falls within the range of 2 to 9 mol (representing the content of R2 alone), and wherein the first rare earth element (R1) and the second rare earth element (R2) respectively diffuse in each of crystal grains forming said dielectric layers and, assuming that, in the crystal grains each having an average grain diameter D, a ratio of a depth d1 of a diffusion layer of the first rare earth element (R1) from the surface of the crystal grain relative to the diameter D of the crystal grain is given as X1(%) and a ratio of a depth d2 of a diffusion layer of the second rare earth element (R2) from the surface of the crystal grain relative to the diameter D of the crystal grain is given as X2(%), the depth d2 of the diffusion layer of the second rare earth element (R2) reaches deeper than the depth d1 of the diffusion layer of the first rare earth element (R1) and a relationship of X1=10 to 35% and X2>X1 (synonymous with d2>d1) is established.