LOW VOLTAGE 3 V OPERATION OF FERROELECTRIC MULTI-LAYER STACK MFIS STRUCTURE DEVICE FORMED BY PLASMA PHYSICAL VAPOR DEPOSITION AND OXYGEN RADICAL TREATMENT

摘要

We have successfully developed a technology that crystallizes a thin ferroelectric film on an insulator such as SiO_2 directly. A very thin (100 nm) and low dielectric constant ferroelectric Sr_2(Ta_(1-x)Nb_x)_2O_7 (STN, x = 0.3) film with high ferroelectric performance has been formed on SiO_2 by repeating the 5 nm STN deposition and oxygen radical treatment 20 times. Using this technology, 3 V operation of the ferroelectric multi-layer stack MFIS (FMLS-MFIS) structure device has been successfully achieved and 0.4 V memory window of the C-V hysteresis curve is obtained. More than 3 days retention time can be obtained under 3 V operation.