How is Ferroelectric RAM Operated?

[Anthus]

Hi,
the schematic unit cell in DRAM is drawn below:
https://docs.google.com/file/d/0BzvjZoZeQg3nd1JYNTdGOTdIS2c/edit?usp=sharing

Here, "zero" or "one" are simply capacitor charged or not. So to write a bit, we attach (or not) a source (Vcc) voltage with switch WBIT.

In the case of FeRAM, we have a ferroelectric crystal inside a capacitor. Now, to write a bit, we have to switch polarization of ferroelectric, thus we have to be able to attach a voltage also of the opposite sign. First idea is to replace source and ground, but it is probably not smart solution. It seems to be more complicated. Does anybody know how is it solved?

 

[Baluncore]

Attached is .pdf

 

[Anthus]

So, the voltage is somehow reversed. Thank you.