Next generation electronic memory
A layer of polymer on a layer of aluminum oxide shows an electronic memory effect. The electrical resistance of the stacked layers can be switched between two different values by applying voltage pulses. The memory can be read without modifying the contained information and no power is required to keep the information. This type of electronic memory is being considered as future replacement of the actual flash memory (USB stick) that we use presently. The main advantage is that the polymer oxide memory cell can be made much smaller than a conventional memory cell.
Before the memory effect occurs, the layers need to be especially prepared by applying a short high voltage pulse (forming). Presently this forming is not understood and difficult to control. This is the main drawback of this new technology. It is believed that the high voltage modifies the chemical structure of the oxide leading to the formation of conducting channels or filaments.
To understand the electrical behaviour of the polymer-oxide stack, we use several investigation techniques: impedance spectroscopy, quasi-static capacitance voltage, voltage pulses… By variation of the materials, we try to relate physical phenomenon to solid state physics: charge transport in polymer, mechanisms of forming and switching.