12-03-2012, 03:43 PM
ovonic unified memory
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INTRODUCTION
We are now living in a world driven by various electronic
equipments. Semiconductors form the fundamental building blocks
of the modern electronic world providing the brains and the memory
of products all around us from washing machines to super
computers. Semi conductors consist of array of transistors with each
transistor being a simple switch between electrical 0 and 1. Now
often bundled together in there 10’s of millions they form highly
complex, intelligent, reliable semiconductor chips, which are small
and cheap enough for proliferation into products all around us.
PRESENT MEMORY TECHNOLOGY SCENARIO
As stated, revising the memory technology fields ruled by
silicon technology is of great importance. Digital Memory is and has
been a close comrade of each and every technical advancement in
Information Technology. The current memory technologies have a lot
of limitations. DRAM is volatile and difficult to integrate. RAM is high
cost and volatile. Flash has slower writes and lesser number of
write/erase cycles compared to others. These memory technologies
when needed to expand will allow expansion only two-dimensional
space. Hence area required will be increased. They will not allow
stacking of one memory chip over the other. Also the storage
capacities are not enough to fulfill the exponentially increasing need.
Hence industry is searching for “Holy Grail” future memory
technologies that are efficient to provide a good solution. Next
generation memories are trying tradeoffs between size and cost.
These make them good possibilities for development.
FUNDAMENTAL IDEAS OF EMERGING MEMORIES
The fundamental idea of all these technologies is the bistable
nature possible for of the selected material. FeRAM works on the
basis of the bistable nature of the centre atom of selected crystalline
material. A voltage is applied upon the crystal, which in turn
polarizes the internal dipoles up or down. I.e. actually the difference
between these states is the difference in conductivity. Non –Linear
FeRAM read capacitor, i.e., the crystal unit placed in between two
electrodes will remain in the direction polarized (state) by the applied
electric field until another field capable of polarizing the crystal’s
central atom to another state is applied.
In the case of Polymer memory data stored by changing the
polarization of the polymer between metal lines (electrodes). To
activate this cell structure, a voltage is applied between the top and
bottom electrodes, modifying the organic material. Different voltage
polarities are used to write and read the cells.
