Dielectric relaxation and breakdown detection of doped tantalum oxide high-k thin films

While TaO/sub x/, HfO/sub x/, ZrO/sub x/, Hf-doped TaO/sub x/, and Zr-doped TaO/sub x/ thin films are promising high-k gate dielectric candidates, their intrinsic reliability has not yet been investigated. In this paper, the authors examine some fundamental reliability aspects of these high-k films through ramp voltage stress testing. By studying dielectric relaxation and analyzing the transient conductivity, the breakdown mode of the tested high-k film is identified; a sensitive method of breakdown detection in ramped voltage tests is proposed and investigated.