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 HfO
₂
TL, the SiO
₂
interfacial layer (IL) was formed which incrased EOT. The HfON device shows on/off current of 3.2 ×10
⁶
at drain voltage ( V
_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 ( V
_PGM
/t
_PGM
) and erase voltage/time ( V
_ERS
/t
_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 V
_PGM
/t
_PGM
and V
_ERS
/t
_ERS
of ±8 V/ 1 μs. Furthermore, it showed larger drain source voltage ( V
_DS
) dependence than HfO
₂
TL by utilizing charge injection from electrode side, which would reduce the operation voltage and increase the operation speed.