Leakage current conduction and noise properties in ZrO2 thin film

초록

We studied the leakage current conduction mechanism and noise properties in metal-oxide -semiconductor (MOS) structure with the atomic layer deposited ZrO2 gate dielectric. Under negative bias voltage, the leakage current in ZrO2 film is caused by the trap assisted tunneling in the low bias region, while the space charge limited conduction controls the leakage current flow in high bias region. In addition, the noise power spectrum in the low bias region appears a Lorentzian-like feature which is the result of the random telegraph signal (RTS) fluctuation based on the trap assisted tunneling process. In the high bias region, a Lorentzian spectrum was degraded and the 1/f noise due to the carrier number fluctuations becomes dominant. We also observed that the current noise fluctuation in the low frequency region is due to the trap assisted tunneling process. This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST) (No. 2009-0075053).