Clarification of anomalous phase-chemistry in ceramic thin films and application for induced properties

本工作的目的是澄清陶瓷薄膜相化学中的反常现象。在这项工作中，“异常”的范围是广泛的固溶体，超晶格，多层薄膜。特别是对脉冲激光沉积（PLD）、金属有机物化学气相沉积（MOCVD）、化学溶液沉积法等，阐明了宽范围的溶解度极限（Sr/Ti比）与MOCVD制备的SrTiO_3薄膜相同，因为晶格常数随组成连续变化。这是非常困难的，以散装形式制备铌掺杂的氧化钇稳定的氧化锆（YSZ），然而，我们发现广泛的溶解度（高达至少20摩尔%）的铌到YSZ的PLD制备的薄膜。Nb的加入改善了YSZ的电学性能，特别是从电容-电压（C-V）特性的角度。

The purpose of this work is to clarify anomalous phenomena in phase-chemistry for ceramics thin films. In this work, the rage of "anomalies" are wide range of solid-solution, superlattice, multi-layered thin films. Especially, the phenomena of "doping" were extensively studied, and relationship between crystal structure and properties were considered for ceramic thin films prepared by several methods such as pulsed-laser deposition (PLD), metal-organic chemical vapor deposition (MOCVD), chemical-solution deposition and etc.It was clarified that wide range of solubiity limit (Sr/Ti ratio) was observed as well as that observed for MOCVD-prepared SrTiO_3 films because continuous change of lattice parameter was observed with composition. It is very difficult to prepare Nb-doped yttria-stabilized zirconia (YSZ) in the bulk form, however, we found wide solubility (up to at least 20 mol%) of Nb into YSZ for PLD-prepared films. The addition of Nb improved electrical properties of YSZ, especially from the point of capacitance-voltage (C-V) characteristics.