聚焦离子束沉积铂纳米导线的电学失效机理

Electrical Failure Mechanism of Pt Nanowire Deposited by Focused Ion Beam

研究了聚焦离子束(FIB)沉积Pt纳米导线的电学失效行为及其机理。FIB沉积Pt纳米导线在集成电路修复和微型电极制备等领域有重要应用,其电学特性及失效行为研究对器件结构设计及性能测试具有重要意义。直流电学测试中电压接近9 V时,电流快速上升并发生断路。经扫描电子显微镜(SEM)和原位X射线能谱(EDS)分析发现,断路后Pt纳米导线中有球状结构析出,球状结构中Pt与C的原子数分数之比是原始薄膜中的4倍,周围物质变得疏松甚至发生局部断裂,且Pt的原子数分数降低,从而形成不导电结构。进一步对样品进行升温电学测试,结果表明,在120℃以上Pt纳米导线在内部电流与外部加热共同作用下发生Pt晶粒生长及团聚,使Pt空缺的间隙变大,从而造成Pt纳米导线的电学失效。

The electrical failure behavior and mechanism of Pt nanowire deposited by focused ion beam(FIB) were studied.The Pt nanowire deposited by FIB has important applications in the fields of integrated circuit modification, micro-electrode fabrication, etc.Its electrical characteristics and the study of the failure behavior were of great significance for device structure design and performance test.In the DC electrical test, when the voltage increased close to 9 V,the current rised rapidly and broke down.Scanning electron microscopy(SEM) and in-situ X-ray energy dispersive spectroscopy(EDS) analyses show that the spherical structure precipitates from the Pt nanowire after breakdown.The atom fraction ratio of Pt and C in the spherical structure is 3 times higher than that in the original film.The surrounding materials become loose and even fracture locally, meanwhile the atom fraction of Pt decreases, therefore it becomes a non-conductive structure.The heating electrical test result of samples shows that above 120 ℃,under the combined action of the internal current and external heating, Pt grains grow and agglomerate, which enlarges Pt vacancy gaps and causes the electrical failure of the Pt nanowire.