通过介质层预注电荷提高射频微机电开关性能

Improved working properties of RF MEMS switch by pre-injecting charges into the dielectric layer

为提高电容式静电驱动射频(radio frequency,RF)微机电系统(micro-electro-mechanical systems,MEMS)开关的驱动与使用性能,进行了模拟仿真。分析发现:随着开关次数的增加,介质层积累的电荷可以引起电容-电压曲线的偏移,进而引起开关的失效。为了避免这样的失效,通过在界面介质层内预注入适量的静电荷,并采用相应的新的驱动模式,可以在不改变开关结构参数的条件下,将最佳驱动电源电压幅值降为约原设计幅值1/2。对仿真分析的结论进行相关实验,一定程度上验证了设想的可行性。同时分析还发现如果采用适当的介电层材料,利用界面预注入的静电荷可能可以减慢电荷在介电层中的积累速度,从而维持驱动电压的稳定并延长开关的使用寿命。

Simulations were used to analyze the driving and working properties of radio frequency micro-electro-mechanical system （RF MEMS） switch. The results show that the capacity-voltage curve is shifted by the accumulation of trapped charges within the dielectric layer, which will lead to a failure of the RF switch. Failure can be presented by pre-injected charges into the dielectric layer with a revised voltage driving mode. Simulations and tests show that the driving voltage can be optimized to half of its original amplitude without varying the original structure and design of the RF switch. Simulations agree well with experiments to validate the method＇s feasibility. The pre-injected charges prevent further trapped charges, therefore prolonging the switch lifetime.