Title: Chalcogenide memories<br><br>

Speaker: Ilya Karpov<br><br>

Abstract: <br>
Chalcogenide phase-change materials, commercially proven materials used
in rewriteable CD and DVD optical disks, have a unique property to
change resistivity by many orders of magnitude between its amorphous and
polycrystalline phases.  This electrical feature resulted in our
interest to evaluate the materials for non-volatile memory applications.
Product advantages of chalcogenide-based electrical devices include 1)
potential for low cost from competitive cell size and relative process
simplicity, 2) large read margin from large dynamic range of resistance,
4) relative ease of embedding into a state-of-the-art baseline CMOS
logic process.
Ge2Te2Sb5 (GST225) material is one of the most actively studied phase
change chalcogenides. Phase change characteristics and other physical
properties of GST225 alloys will be reviewed. Basic elements of device
operation, key device parameters as well as various proposed memory cell
designs will be discussed. Complexities of the physical phenomena during
device operation will be illustrated and emphasized. I will also discuss
our focus in successful collaboration with Prof. V. Karpov team.