GPa量级交变机械应力加载下纳米薄膜FET的电特性研究

The further development of NEMS resonators reduces feature size from the nano-beam to nano-wire. Current drive detection of the MEMS resonator is unable to achieve such accuracy. The field-effect based detection method is not affected by the resonator size change. But in this method, the FET channel will be subjected to external environmental impact such as large deformation, GPa-level mechanical stress, and alternating mechanical stress. The current research of the stress in channel only focuses on the AC stress, residual stress and thermal stress, MPa grade stress in IC process. The research of alternating mechanical stress and GPa order magnitude stresses on nanofilm FET characteristics is necessary. .In project, electrical property of nano FET under Gpa alternating mechanical stress is measured and FET parameter is extracted. And we develops the way of Gpa stress loaded by probe and alternating mechanical stress by mass vibration; FET parasitic effects will be released in principle.

随着纳机电谐振器进一步发展, 特征尺寸由纳米梁减小至纳米线。目前应用于MEMS谐振器的驱动检测已无法达到此精度，基于场效应原理的检测方法不以谐振器尺寸减小而改变，是纳米线谐振器检测的革新。但纳米线上场效应管(FET)在谐振器振动时,会周期性地发生弯曲形变,产生的交变机械应力可达GPa量级,寄生效应会改变FET部分特性参数,干扰纳米梁谐振器本身的检测信号。扣除交变机械大应力导致的背景寄生信号，对校准谐振器场效应检测十分重要。关于GPa级交变大应力研究少有报道,目前文献对交变应力研究仅限于交变电应力，且研究的应力来自IC工艺中残余应力和热应力等,仅达MPa级。本项目测试交变大应力下纳米薄膜FET的电性能，提取FET相关特性参数研究寄生效应。发展探针下压逐点线性加载Gpa级应力、质量块振动产生机械交变应力等测试手段,从原理上减小交变大应力产生的FET寄生效应对纳米谐振器检测的影响。

纳机电谐振器的进一步发展使其特征尺寸由纳米梁减小至纳米线，目前应用于MEMS谐振器的驱动检测已无法达到此精度，基于场效应检测的方法不以谐振器尺寸的减小而改变。但MOSFET会受到交变机械应力影响，且大弯曲变形时应力可达GPa量级。目前报道的沟道交变应力研究仅限于交变电应力，且IC工艺中残余应力、热应力等仅达MPa级。关于GPa 级交变应力对纳米薄膜MOSFET特性影响的研究十分必要。.本项目集成下压探针与数显螺旋测微仪，原位探测下压位移实现逐点线性加载Gpa级大应力，加载应力的误差范围1%内，测量纳米薄膜SOI-MOSFET的输出转移特性提取相关参数；并建立沟道压阻理论与界面效应模型，验证Gpa级应力对载流子特性影响；研究大应力下MOSFETs的阈值电压及输出电流相对变化温度特性；结合高温大应力下漏端电流的失效机制，分析温度及大应力对栅电流的影响，结合界面缺陷态产生机制，研究机械交变应力的频率、振幅对器件阈值电压偏移、电学可靠性的影响。为发展硅纳米线谐振器的MOSFET 检测奠定基础。