Correct me if I'm wrong, but it sounds like you want to stack one memory device on top of another.

I think the biggest problem with this scenario is that the pin functions are identical, so if you stack, you connect the read and write and chip-select signals. You'll have to isolate at least the chip selects, otherwise you write the same info to both chips, and worse, you get bus contention when trying to read.

So, no, you really don't want to do what you're asking, if in fact this is what you're asking.

(Turns out that this is exactly how some memory chips are made, although the dice are stacked inside the package and the chip select/strobe issue is sorted out.)

-a