LANTHANUM OXIDE-BASED SINTERED OBJECT, SPUTTERING TARGET COMPRISING THE SINTERED OBJECT, PROCESS FOR PRODUCING LANTHANUM OXIDE-BASED SINTERED OBJECT, AND PROCESS FOR SPUTTERING TARGET PRODUCTION USING THE PROCESS

摘要

A lanthanum oxide-based sintered compact having lanthanum oxide as a basic component, wherein the sintered compact contains one or more of titanium oxide, zirconium oxide and hafnium oxide with the remainder being lanthanum oxide and unavoidable impurities. A method of producing a lanthanum oxide-based sintered compact, wherein La₂(CO₃)₃ powder or La₂O₃ powder as lanthanum oxide raw material powder and one or more of TiO₂, ZrO₂ and HfO₂ powders as an additive oxide are used, blending and mixing are performed so that the composition ratio of metal components of the additive oxide becomes a predetermined value based on the metal conversion, the mixed powder is thereafter heated and synthesized in the atmosphere, the synthesized material is subsequently pulverized to obtain powder, and the synthesized powder is thereafter hot pressed into a sintered compact. This invention prevents the sintered compact from combining with moisture or carbon dioxide gas to form hydroxide or the like and changing into powder form, and enables the long term storage thereof. Moreover, as a result of performing deposition with this sputtering target, oxide for use in a high-k gate insulator film can be efficiently and stably provided.