Oxide dielectric and method for manufacturing same, and solid state electronic device and method for manufacturing same

An oxide dielectric being an oxide (possibly including inevitable impurities) consisting essentially of bismuth (Bi), niobium (Nb), and oxygen, the oxide dielectric comprising:

• a first crystal phase of a pyrochlore-type crystal structure;
• and
• a second crystal phase of a β-BiNbO4-type crystal structure,
• wherein a content of the second crystal phase is 1.43 or more and 4.67 or less when a content of the first crystal phase is assumed to be 1.

A method for manufacturing an oxide dielectric, the method comprising:

• a heating step of heating, in an oxygen-containing atmosphere, a precursor derived from a precursor solution, as a starting material, comprising a bismuth (Bi)-containing precursor and a niobium (Nb)-containing precursor as solutes, to form an oxide (possibly including inevitable impurities) consisting essentially of bismuth (Bi), niobium (Nb), and oxygen, and to control contents of a first crystal phase of a pyrochlore-type crystal structure and a second crystal phase of a β-BiNbO4-type crystal structure, the oxide comprising:
• the first crystal phase of the pyrochlore-type crystal structure having a dielectric constant that decreases with increasing temperature of the oxide in a temperature range of 25° C. or more and 120° C. or less;
• and
• the second crystal phase of the β-BiNbO4-type crystal structure having a dielectric constant that increases with increasing temperature of the oxide in a temperature range of 25° C. or more and 120° C. or less.

A method for manufacturing an oxide dielectric, the method comprising:

• a heating step performed in such a manner that a content of a second crystal phase of a β-BiNbO4-type crystal structure is controlled to be 1.43 or more and 4.67 or less when a content of a first crystal phase of a pyrochlore-type crystal structure is assumed to be 1, by heating, in an oxygen-containing atmosphere, a precursor derived from a precursor solution, as a starting material, comprising a bismuth(Bi)-containing precursor and a niobium (Nb)-containing precursor as solutes, to form an oxide (possibly including inevitable impurities) consisting essentially of bismuth (Bi), niobium (Nb), and oxygen, the oxide comprising:
• the first crystal phase of the pyrochlore-type crystal structure;
• and
• the second crystal phase of the β-BiNbO4-type crystal structure.