Patent ID: 8765026

Claim:
A tablet for vapor deposition which is made of an indium oxide sintered body containing cerium as a dopant, and which has a relative density of 50% to 80%, both inclusive, the tablet for vapor deposition characterized in that crystal grains appearing on a fracture surface of the indium oxide sintered body have such a distribution of crystal grain amounts that the percentage (most frequent crystal grain percentage) due to crystal grains having a grain diameter corresponding to a highest peak is 20% or less, each of the crystal grain amounts being obtained by multiplying the number of crystal grains by a grain diameter of the crystal grains, wherein the “most frequent crystal grain percentage” is determined for the fracture surface of the indium oxide sintered body through the following steps (1) to (5): (1) drawing three parallel straight lines at any positions on a SEM image of the fracture surface of the indium oxide sintered body, and measuring lengths defined by grain boundary portions of crystal grains positioned on the three straight lines as “grain diameters (crystal grain diameters) of the crystal grains”; (2) sectioning the range of the measured grain diameters (crystal grain diameters) at intervals of 0.34 μm, and counting “the number of crystal grains” in each of the sections divided at the 0.34-μm intervals; (3) with the “center value” of each of the sections being used as a representative value of the “grain diameters (crystal grain diameters) of the crystal grains” in the section, defining a value obtained by multiplying the “number of crystal grains” by the “crystal grain diameter (center value)” as a “crystal grain amount”; (4) then, determining the “crystal grain amount” for each of the sections, and calculating the percentage of each of the “crystal grain amounts” relative to the total of the “crystal grain amounts”; and (5) with a peak having the maximum value among the calculated percentages being defined as the “highest peak,” determining the percentage due to the crystal grains having the grain diameter corresponding to the highest peak as the “most frequent crystal grain percentage”.