The charge loss mechanism in a hafnium oxide (HfO2)dielectric dot flash memory is investigated. We measure the temperature and time dependence of a charge loss induced gate leakage current in a large area cell directly. We find that 1) the charge loss is through a top oxide in the cell and 2) the stored charge emission process exhibits an Arrhenius relationship with temperature, as opposed to linear temperature dependence in a semiconductor-oxide-nitride-oxide-semiconductor flash memory. A thermally activated tunneling front model is proposed to account for the charge loss behavior in a HfO2 dot flash memory.
- Charge retention loss
- Hafnium oxide HfO dot flash
- Thermally activated tunneling