Dear MEMS experts,

I have encountered a huge 1/frequency type real part impedance when I
use suspended polysilicon membrane (either doped with phosphorus or undoped)
as moving electrode (in high kilohertz and low megahertz range) and
highly phosphorus doped silicon substrate (seperated by nitride) as
fixed electrode to form a variable capacitor. Both electrodes are
covered with aluminum to give better conductivity and form the bonding pads.
Does anyone observe the same problem or give me a clue of what is going on?
Is there any good reference for this type of work? Thank you very much.

Best regards.                                          Sincerely Yours,
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                                XueCheng JIN
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