小型飞行器跟踪地面运动目标技术研究

为提高跟踪与探测的能力,研究了利用小型飞行器对地面低速运动目标的跟踪技术.通过对初始盘旋半径、初始盘旋位置以及飞机倾斜角这几个参数之间关系的分析与仿真,表明随初始相对位置的不同,最小初始盘旋半径取值在200m～500m之间不等,飞机的倾斜角就能保持在30°以下,从而有效地实现对运动目标的实时贴近跟踪与探测,仿真结果对实际系统的应用具有重要的参考价值.     

后栅工艺高k/金属栅结构NMOSFET偏压温度不稳定性特性研究

本文对后栅工艺高k/金属栅结构NMOSFET偏压温度不稳定性特性进行了研究。在加速应力电压和高温条件下,NMOSFET的阈值电压的退化与时间呈幂指数关系。然而幂指数随应力电压的增大而减小;在本文中,应力从0.6V到12V,幂指数则相应的由0.26减小到0.16。通过对应力前后器件的亚阈值特性分析,在应力过程中没有界面态产生。根据实验数据提取到数值为0.1eV的热激活能,表明偏压温度不稳定性是由栅介质中预先存在的陷阱俘获从衬底隧穿的电子造成的。恢复阶段的测试显示阈值电压的退化与对数时间呈线性关系,同时可以用确定的数学表达式来表明其与应力电压和温度之间的关系。     

超薄SiO2/HfO2双层栅介质的时变击穿特性和击穿机制的研究

The characteristics of TDDB （time-dependent dielectric breakdown） and SILC （stress-induced leakage current） for an ultra-thin SiO2/HfO2 gate dielectric stack are studied. The EOT （equivalent-oxide-thickness） of the gate stack （Si/SiO2/HfOz/TiN/TiA1/TiN/W） is 0.91 am. The field acceleration factor extracted in TDDB experi- ments is 1.59 s.cm/MV, and the maximum voltage is 1.06 V when the devices operate at 125 ℃ for ten years. A detailed study on the defect generation mechanism induced by SILC is presented to deeply understand the break- down behavior. The trap energy levels can be calculated by the SILC peaks： one S1LC peak is most likely to be caused by the neutral oxygen vacancy in the HfO2 bulk layer at 0.51 eV below the Si conduction band minimum; another SILC peak is induced by the interface traps, which are aligned with the silicon conduction band edge. Fur- thermore, the great difference between the two SILC peaks demonstrates that the degeneration of the high-k layer dominates the breakdown behavior of the extremely thin gate dielectric.