Memory characteristics and tunneling mechanism of Pt nano-crystals embedded in HfAlOx films for nonvolatile flash memory devices

A non-volatile flash memory device based on metal oxide semiconductor (MOS) capacitor structure has been fabricated using platinum nano-crystals(Pt-NCs) as storage units embedded in HfAlOx high-k tunneling layers. Its memory characteristics and tunneling mechanism are characterized by capacitance-voltage(C-V) and flat-band voltage-time(ΔVFB-T) measurements. A 6.5 V flat-band voltage (memory window) corresponding to the stored charge density of 2.29 × 1013 cm−2 and about 88% stored electron reserved after apply ±8 V program or erase voltage for 105 s at high frequency of 1 MHz was demonstrated. Investigation of leakage current-voltage(J-V) indicated that defects-enhanced Pool-Frenkel tunneling plays an important role in the tunneling mechanism for the storage charges. Hence, the Pt-NCs and HfAlOx based MOS structure has a promising application in non-volatile flash memory devices.