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DEVELOPMENT OF HIGH PERFORMANCE STRESS SENSOR USING SEMICONDUCTING BARIUM TITANATE THIN WIRES WITH GIANT PIEZORESISTIVE EFFECTS

使用具有巨大压阻效应的半导体钛酸钡细线开发高性能应力传感器

基本信息

批准号：
10555214
负责人：
KUWABARA Makoto
金额：
$ 8.13万
依托单位：
UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

The objective of this study is to clear the mechanism of the piezoresistive effect in semiconducting barium titanate ceramics and to establish a procedure for producing high-peformance stress sensors using barium titanate thin wires with a single grain boundary structure, which exhibit a significantly large piezoresistive effect at room temperature.The obtained results are summarized as follows :1) Preparation of semiconducting barium titanate thin ceramic wires : We succeeded in producing semiconducting barium titanate thin ceramic wires, with a diameter of 10-20 μm, consisting of single grains joined together in series by drawing green fibers from slurry, followed by sintering at 1370℃ in air.2) Observation of giant piezoresistive effects : An extremely large piezoresistive effect of more than 10^7 in gauge factor (defined as the resistance change ratio per strain) was observed for some of the single grain boundaries formed in semiconducting barium titanate thin ceramic wires produce … More d.3) Analysis of the 90゜ domain wal motion under mechanical stresses : We directly observed how 90゜ domain walls move in a BaTiO_3 ceramic wire under tensile and compressive stresses with a polarizing microscope. In this experiment, we found that just as a 90゜ domain wall arrived at a grain boundary, associated with an instantaneous change of the domain morphology in the vicinity of the grain boundary, the grain boundary resistivity drastically changed. It has been for the first time confirmed that the piezoresistivity in semiconducting barium titanate ceramics is directly connected with the change of the domain morphology in the vicinity of grain boundaries.4) Analysis of the piezoresistivity mechanism : We were able to successfully determine the direction of spontaneous polarization in the two ferroelectric domains adjacent to a 90゜ domain wall moving in a single grain under mechanical stresses. From the obtained results it has been found that the meachanism of the piezoresistivity in semiconducting barium titanate ceramics can be interpreted by a surface charge compensation model by spontaneous polarization at grain boundaries.5) Est ablishment of a procedure for producing high-performance stress sensor devices : We made prototype stress sensor devices using semiconducting barium titanate thin ceramic wires, which exhibit a large piezoresistive effect at room temperature, and confirmed their stress sensor function working as expected though some problems such as reproducibility remain. Less

本研究的目的是明确半导体钛酸钡陶瓷中压阻效应的机制，并建立一种在室温下表现出明显的压阻效应的单晶界结构钛酸钡细线生产高性能应力传感器的工艺。结果如下：1)半导体钛酸钡细陶瓷丝的制备：通过从浆料中拉伸绿纤维，在1370℃空气中烧结，成功制备了直径为10 ~ 20 μm的单晶粒串联的半导体钛酸钡细陶瓷丝。2)观察到巨大的压阻效应：在半导体钛酸钡细陶瓷丝中形成的一些单晶界中，观察到超过10^7的压阻效应（定义为每应变的电阻变化比）产生…更多d.3)机械应力下90畴壁运动的分析：我们使用偏光显微镜直接观察了在拉伸和压缩应力下BaTiO_3陶瓷丝中90个畴壁的移动情况。在本实验中，我们发现，就在90畴壁到达晶界时，伴随着晶界附近畴形态的瞬时变化，晶界电阻率发生了急剧变化。首次证实了半导体钛酸钡陶瓷的压阻性与晶界附近畴形态的变化有直接关系。4)压阻机制分析：我们能够成功地确定在机械应力下在单个晶粒中移动的90畴壁相邻的两个铁电畴中的自发极化方向。所得结果表明，半导体钛酸钡陶瓷的压阻机理可以用晶界自发极化的表面电荷补偿模型来解释。5)建立高性能应力传感器器件的生产流程：我们使用半导体钛酸钡细陶瓷线制作了原型应力传感器器件，该器件在室温下表现出较大的压阻效应，并证实其应力传感器功能符合预期，但仍存在再现性等问题。少