Investigation of the HfON tunneling layer of MONOS device for low-voltage and high-speed operation nonvolatile memory application

We investigated the reduction of equivalent oxide thickness (EOT) of the in-situ formed Hf-based metal/oxide/nitride/oxide/silicon (MONOS) structure nonvolatile memory (NVM) device utilizing the HfON tunneling layer (TL). In case of the HfO2 TL, the SiO2 interfacial layer (IL) was formed which incrased EOT. The HfON device shows on/off current of $3.2 \times 10^{6}$ at drain voltage ( $\text{V}_{\mathrm{ D}}$ ) of 0.05 V, subthreshold swing (SS) of 113 mV/dec., and memory window (MW) of 3.9 V at the program voltage/time ( $\text{V}_{\mathrm{ PGM}}/\text{t}_{\mathrm{ PGM}}$ ) and erase voltage/time ( $\text{V}_{\mathrm{ ERS}}/\text{t}_{\mathrm{ ERS}}$ ) of ±8 V/100 ms. Although, it shows low retention characteristics with 50% after 10 years, low-voltage and short-pulse operation were achieved, such as MW of 1 V at $\text{V}_{\mathrm{ PGM}}/\text{t}_{\mathrm{ PGM}}$ and $\text{V}_{\mathrm{ ERS}}/\text{t}_{\mathrm{ ERS}}$ of ±8 V/ $1~\mu \text{s}$ . Furthermore, it showed larger drain source voltage ( $\text{V}_{\mathrm{ DS}}$ ) dependence than HfO2 TL by utilizing charge injection from electrode side, which would reduce the operation voltage and increase the operation speed.