微机电系统微尺度间隙的脉冲击穿特性

利用微机电系统(MEMS)工艺制备了5~40 m间隙的金属铝薄膜电极，测取了不同间隙下施加纳秒方波脉冲时的击穿电压，得到击穿电压和平均场强随电极间隙的变化规律，研究了脉宽、极性对击穿电压的影响，结合击穿后微电极扫描电镜观察结果讨论了其击穿机理，并与相同试样在直流下的结果进行了对比。研究表明:击穿电压随微间隙距离的增大而增大，击穿场强则随着间隙的增大迅速减小；与直流同间隙的击穿电压相比，脉冲作用下的击穿电压并不像宏观尺度下那样高出很多；试样击穿机理应为流注理论。在脉冲作用下，阳极出现了分层熔化现象，由于作用时间很短，阳极表面并未出现类似于直流击穿时留下的坑洞；阴极则出现了溅射沉积现象，只是沉积物质相对较少。

Pulse breakdown characteristics of microscale gap in micro-electro-mechanical system

Micro-electrodes with gaps of 5-40 micrometers were prepared by depositing 400-nm thick Al film on insulator using the micro-electro-mechanical system(MEMS) manufacturing process. Breakdown voltages of different electrode gaps under different pulse polarity and nanosecond pulse widths were measured on test samples. Moreover, the breakdown mechanism was discussed through comparing the observed results of samples after breakdown by use of scanning electron microscope(SEM) and the results of the same samples under DC. In conclusion, the breakdown voltage increases with the gap distance under nanosecond pulse, but the breakdown electric field descends sharply while the gap distance increases. Compared to the breakdown voltage under DC, pulse breakdown voltage is not too much higher, which is different from the results in the case of macro distances. Analyses show that the mechanism of the breakdown is the streamer theory, and the anode is melted layer by layer, while the cathode is sputtered with metal material.