Long retention and low voltage operation using IrO/sub 2/HfAlO/HfSiO/HfalO gate stack for memory application

We demonstrate electrical properties of an advanced memory structure with high-k dielectric stack of HfAlO/HfSiO/HfXIO and p-type metal gate IrO₂. Combining advantages of high-k HfAlO, good trapping capability of HfSiO, and high work function of the IrO₂ gate, we were able to attain much better retention with 10-year DeltaV_th decay ratio within 18%, higher erasing speed with DeltaV_th of 3V within 0.5ms at Vg equiv -12V, and lower operation voltage as well as lower reading voltage, compared to other contending device structures