Electrical and physical properties of HfO2 as gate dielectrics using various thickness of TaN electrodes for MIS capacitors

MIS capacitors with 16-nm high-k dielectric HfO2 and 50–150 nm TaN electrode were studied after post-metal-annealing (PMA) at various conditions. The effect of TaN thickness on electrical and physical properties is summarized. It has been found that the thermal stability of the TaN/HfO2 depends on TaN thickness. A reduction of leakage current and an increase of breakdown voltage were obtained with 50-nm TaN after PMA at 500 °C. The interface quality and the time-dependent dielectric breakdown (TDDB) characteristics were also improved. On the other hand, degradation after PMA was observed in HfO2 capped with 100-nm and 150-nm TaN.

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► TaN/HfO2 MIS capacitors with TaN thicknesses of 50–150 nm were characterized.
► Optimization of TaN metal thickness and PMA temperature is important.
► 50-nm TaN after 500–600 °C PMA exhibits the best electrical and thermal properties.