The high K gate dielectrics of MOS capacitors with HfZrLaO (standing for HfO2 doped with La and Zr) or HfLaO (standing for HfO2 doped with La) have been fabricated by atomic-layer-deposition (ALD), and the time-dependent-dielectric-breakdown (TDDB) reliability properties have also been investigated. The equivalent oxide thickness (EOT) of HfLaO or HfZrLaO is 0.72 nm or 0.68 nm, respectively. In terms of the gate leakage current density (J(g)) versus EOT (J(g)-EOT) performance, HfZrLaO has a better characteristic in comparison with HfLaO. In terms of TDDB characteristics, the maximum voltages projected to have 10-year TDDB lifetime under 85 degrees C operation for HfZrLaO and HfLaO ultra-thin gate dielectrics are 1.87 V and 2.03 V. respectively. In addition, some important results, such as activation energy and field acceleration parameter, for HflaO and HfZrLaO gate dielectrics are compared and summarized in this research. (c) 2012 Elsevier Ltd. All rights reserved.