Polymer memory – A new way of using plastic as secondary storage

A new memory technology promises to store more data at less cost than the expensive to build silicon chips used by popular consumer gadgets including digital cameras, cell  phones and portable music players. The magical ingredient is not smaller transistors or an exotic material cooked up by the  semiconductor industry. It is a plastic. This new memory does not use transistors to store information.  Instead, bits are written when a strong current passes through a polymer fuse, causing it to blow and change its conductivity.

  I.INTRODUCTION

           While experimenting with a polymer material known as PEDOT, Princeton University researcher Sven Moller determined that although the plastic conducts electricity at low voltages, it permanently loses its conductivity when exposed to higher voltages. Together with colleagues from Hewlett-Packard Laboratories, he developed a method to take advantage of this property to store digital information, which can be stored as collections of ones and zeros. The PEDOT-based memory card consists of a grid of circuits comprising polymer fuses. A large applied current causes specific fuses to “blow,” leaving a mix of functioning and nonfunctioning connections. When a lower current is later used to read the data, a blown fuse blocks current flow and is read as a zero, whereas a working

fuse is interpreted as a one. Because the storage method involves a physical change to the device, it is a so-called WORM–write once, read many times–technology.

II.FEATURES OF POLYMER MEMORY

1. Data stored by changing the polarization of the polymer between metal lines.
2. Zero transistors per bit of storage.
3. Memory is Nonvolatile.
4. Microsecond initial reads. Write speed faster than NAND and NOR Flash.
5. Simple processing, easy to integrate with other CMOS.

III.PLASTIC MEMORY BEING DEVELOPED

            Researchers at Princeton University working with Hewlett-Packard have invented a new form of permanent computer memory that uses plastic, and may be much cheaper and faster than existing silicon circuits. By utilising a previously unknown property of a cheap, transparent plastic called PEDOT short for polyethylenedioxythiophene the inventors say that data densities as high as a megabit per square millimetre should be possible. By stacking layers of memory, a cubic centimeter device could hold as much as a gigabyte and be cheap enough to compete with CDs and DVD. PEDOT is an unusual plastic because it conducts electricity, a property that’s led to it being used for antistatic coatings. However, a sufficiently large pulse of current changes it permanently to an unconducting state, just like a fuse. By putting microscopic pellets of the stuff between two grids of wires, data can be stored by blowing patterns of bits. The memory cannot be rewritten, but can be read very fast and with low power consumption. The biggest challenge is developing production techniques. We are hybridising said the leader of the research group, Princeton professor of electrical engineering Stephen Forrest. We are making a device that is organic the plastic polymer and inorganic thin film silicon at the same time.

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