AVS 62nd International Symposium & Exhibition
    Electronic Materials and Processing Monday Sessions
       Session EM+NS+PS-MoA

Invited Paper EM+NS+PS-MoA5
Materials Selection for Oxide-based Resistive Random Access Memory (RRAM)

Monday, October 19, 2015, 3:40 pm, Room 210E

Session: More Moore! II
Presenter: John Robertson, Cambridge University, United Kingdom of Great Britain and Northern Ireland
Authors: J. Robertson, Cambridge University, United Kingdom of Great Britain and Northern Ireland
Y. Guo, Cambridge University, United Kingdom of Great Britain and Northern Ireland
Correspondent: Click to Email
Resistive random access memory (RRAM) is a main challenger non-volatile memory technology to Flash memory. The favored materials are based on the formation of a conductive filament of oxygen vacancies across a film of a wide gap oxide. However, a wide range of material systems are presently being studied, which use various different switching mechanisms. Materials selection requires us to understand which material properties control each aspect of device performance, such as switching speed, resistance window, retention time and endurance. Here, the energies of various atomic processes in resistive random access memories (RRAM) are calculated for four typical oxides, HfO2, TiO2, Ta2O5 and Al2O3, to define a materials selection process. Oxygen vacancies have the lowest defect formation energy in the O-poor limit, and to dominate the processes. A band diagram defines the operating ranges of Fermi energy and O chemical potential. It is shown how scavenger metals can be used to vary the O chemical potential and thus vary the O vacancy formation energy. The high stability of amorphous phase of Ta2O5 is relevant to the high endurance of its RRAM.