Post-breakdown conduction in metal gate/MgO/InP structures

The electrical behavior of broken down thin films of magnesium oxide (MgO) grown on indium phosphide (InP) substrates was investigated. To our knowledge, this is the first report that identifies the Soft Break Down (SBD) conduction mode in a metal gate/high-kappa/III-V semiconductor structure. It is shown that the leakage current associated with this failure mode follows the power-law model I=aVb for both injection polarities in a voltage range that largely exceeds the one reported for SiO2. We also show that the Hard Break Down (HBD) current is remarkably high, involving significant thermal effects that are believed to be at the origin of the switching behavior exhibited by the I-V characteristics.