The current techniques used for the fabrication of nanosteps are normally done by layer growth and then ion beam thinning. There are also extra films grown on the step surfaces in order to reduce the roughness. So the...The current techniques used for the fabrication of nanosteps are normally done by layer growth and then ion beam thinning. There are also extra films grown on the step surfaces in order to reduce the roughness. So the whole process is time consuming. In this paper, a nanoscale step height structure is fabricated by atomic layer deposition (ALD) and wet etching techniques. According to the traceable of the step height value, the fabrication process is controllable. Because ALD technology can grow a variety of materials, aluminum oxide (Al2O3) is used to fabricate the nanostep. There are three steps of Al2O3 in this structure including 8 nm, 18 nm and 44 inn. The thickness of Al2O3 film and the height of the step are measured by anellipsometer. The experimental results show that the thickness of Al2O3 film is consistent with the height of the step. The height of the step is measured by AFM. The measurement results show that the height is related to the number of cycles of ALD and the wet etching time. The bottom and the sidewall surface roughness are related to the wet etching time. The step height is calibrated by Physikaliseh-Technische Bundesanstalt (PTB) and the results were 7.5±1.5 nm, 15.5±2.0 nm and 41.8±2.1 nm, respectively. This research provides a method for the fabrication of step height at nanoscale and the nanostep fabricated is potential used for standard references.展开更多
硅微谐振压力传感器检测信号的幅值稳定性与频率跟踪性对其性能至关重要,但目前幅值控制与频率跟踪方法的非线性特征会造成谐振器振动频率的非线性变化,限制了传感器综合精度的进一步提升。为降低谐振器振动频率非线性变化的影响,基于...硅微谐振压力传感器检测信号的幅值稳定性与频率跟踪性对其性能至关重要,但目前幅值控制与频率跟踪方法的非线性特征会造成谐振器振动频率的非线性变化,限制了传感器综合精度的进一步提升。为降低谐振器振动频率非线性变化的影响,基于自动增益控制(Automatic gain control,AGC)的线性化分析理论,建立高Q值硅微谐振压力传感器自动增益控制和相位补偿模型,分析AGC幅值控制和频率跟踪线性化的控制特性,以及相位补偿对闭环控制性能的影响。基于自动增益控制(AGC)的自激驱动被证实可使谐振器稳定工作于谐振频率,且保持幅值稳定,通过Simulink/PSpice建模仿真,验证非线性系统线性化分析的准确性。同时基于自动增益控制与相位补偿模型设计与制作的硅谐振压力传感器控制电路,经测试可使整表频率稳定性优于±0.05 Hz@采样周期5 ms,综合精度优于±0.02%FS,实现自动增益控制在谐振压力传感器的工程化应用,解决了谐振器频率跟踪非线性引起的传感器性能下降问题,可广泛应用于高Q值谐振器闭环控制。展开更多
基金Supported by National Natural Science Foundation of China(Grant No.51175418)Major Research Program on Nanomanufacturing of National Natural Science Foundation of China(Grant No.91323303)+1 种基金Fund of the State Key Laboratory of Precision Measuring Technology and Instruments(Tianjin University and Tsinghua University)of China(Grant No.PIL1403)Collaborative Innovation Center of Suzhou Nano Science and Technology of China
文摘The current techniques used for the fabrication of nanosteps are normally done by layer growth and then ion beam thinning. There are also extra films grown on the step surfaces in order to reduce the roughness. So the whole process is time consuming. In this paper, a nanoscale step height structure is fabricated by atomic layer deposition (ALD) and wet etching techniques. According to the traceable of the step height value, the fabrication process is controllable. Because ALD technology can grow a variety of materials, aluminum oxide (Al2O3) is used to fabricate the nanostep. There are three steps of Al2O3 in this structure including 8 nm, 18 nm and 44 inn. The thickness of Al2O3 film and the height of the step are measured by anellipsometer. The experimental results show that the thickness of Al2O3 film is consistent with the height of the step. The height of the step is measured by AFM. The measurement results show that the height is related to the number of cycles of ALD and the wet etching time. The bottom and the sidewall surface roughness are related to the wet etching time. The step height is calibrated by Physikaliseh-Technische Bundesanstalt (PTB) and the results were 7.5±1.5 nm, 15.5±2.0 nm and 41.8±2.1 nm, respectively. This research provides a method for the fabrication of step height at nanoscale and the nanostep fabricated is potential used for standard references.
文摘硅微谐振压力传感器检测信号的幅值稳定性与频率跟踪性对其性能至关重要,但目前幅值控制与频率跟踪方法的非线性特征会造成谐振器振动频率的非线性变化,限制了传感器综合精度的进一步提升。为降低谐振器振动频率非线性变化的影响,基于自动增益控制(Automatic gain control,AGC)的线性化分析理论,建立高Q值硅微谐振压力传感器自动增益控制和相位补偿模型,分析AGC幅值控制和频率跟踪线性化的控制特性,以及相位补偿对闭环控制性能的影响。基于自动增益控制(AGC)的自激驱动被证实可使谐振器稳定工作于谐振频率,且保持幅值稳定,通过Simulink/PSpice建模仿真,验证非线性系统线性化分析的准确性。同时基于自动增益控制与相位补偿模型设计与制作的硅谐振压力传感器控制电路,经测试可使整表频率稳定性优于±0.05 Hz@采样周期5 ms,综合精度优于±0.02%FS,实现自动增益控制在谐振压力传感器的工程化应用,解决了谐振器频率跟踪非线性引起的传感器性能下降问题,可广泛应用于高Q值谐振器闭环控制。