Dear sir:
I'am a postgraduate student from Tsinghua University in China. I'am studying in
optical switch. Now I have some difficulties and need your help.
The electrostatic actuation switch is fabricated using a standard surface-
micromaching technique. A 0.155-um-thick SiO2 is thermally grown on the highly
p-doped silicon substrate which is the back electrode. A 0.16um-thick silicon
nitride is deposited by LPCVD. The two layers is served as isolation. A 30-nm-
thick Cr and a 200-nm-thick Au are splashed on the surface of the silicon
nitride to make the electrode. In theory, the resistance between the two
electrodes should be infinite. But we measured that the resistance is only
hundreds ¦¸cm.
Cr is served as hold up layer which prevent the leakage of Au. Perhaps the Cr is
so thin that Au contacts with the substrate at some point.Or is the isolation
layer too thin? Maybe there will be other reasons ? Could you give me an answer?
Thanks a lot.
                                Yours truly
                                                         Suyan Liu








            liusy@post.pim.tsinghua.edu.cn