基于MEMS技术的离子门设计与制备

Design and Fabrication of MEMS-Based Ion Gate

为了提高小型离子迁移谱仪分辨率,基于微电子机械系统(MEMS)技术设计并制备了Bradbury-Nielsen(BN)离子门。首先简要介绍离子迁移谱仪原理及结构,其次通过SIMION软件对漂移管进行建模,利用统计扩散模拟(SDS)多物理场的仿真程序模拟离子团在漂移管中的运动情况。根据理论分析和有限元数值仿真研究了BN离子门电极丝参数对离子迁移谱仪性能的影响,并确定参数的优化值为:电极丝间距200μm、直径20μm。最后根据工艺条件设计了适用于小型离子迁移谱仪的MEMS离子门,并绘制了相应的掩模版图形。在此基础上详细阐述了采用剥离工艺和深反应离子刻蚀(DRIE)工艺基于4英寸(1英寸=2.54cm)绝缘体上硅(SOI)晶片制备MEMS离子门器件的方法,对比了样品电极丝参数的设计值和测量值,并验证器件的平整度。

In order to improve the resolution of small-scale ion mobility spectrometer,Bradbury-Nielsen(BN)ion gate was designed and fabricated based on micro-electromechanical system(MEMS)technology.Firstly,the principle and structure of ion mobility spectrometer were briefly introduced.Secondly,the drift tube was modeled by SIMION software,and the motion of ion clusters in the drift tube was simulated by statistical diffusion simulation(SDS)multiphysical field simulation program.The influences of BN ion gate electrode wire parameters on the performance of ion mobility spectrometer were studied based on theoretical analysis and finite element numerical simulation.The optimized parameters were determined as follows:the electrode wire spacing 200μm and the diameter 20μm.Finally,according to the process conditions,the MEMS-based ion gate suitable for small ion mobility spectrometer was designed and the corresponding mask graphics were drawn.On this basis,the fabrication method of the MEMS-based ion gate device based on the 4-inch(1 inch=2.54 cm)silicon on insulator(SOI)wafer using lift-off and deep reaction ion etching(DRIE)processes was described in detail.The designed values and measured values of electrode wire parameters of the sample were compared,and the flatness of the device was verified.