Remarkable Resistance Change in Plasma Oxidized TiO_x/TiN_x Film for Memory Application

We report the experimental phenomenon of large resistance change in
plasma oxidized TiO_x/TiN_x film fabricated on W bottom-electrode-contact (W-BEC) array. The W-BEC in diameter 260nm is fabricated by a 0.18μm CMOS technology, and the TiO_x/TiN_x cell array is formed by rf magnetron sputtering
and reactive ion etching. In current--voltage (I--V) measurement for current-sweeping mode, large snap-back of voltage is observed, which indicates that the sample changes from high-resistance state (HRS) to low-resistance state (LRS). In the I--V measurement for voltage-sweeping mode, large current collapse is observed, which indicates that the sample changes from LRS to HRS. The current difference between HRS and LRS is about two orders. The threshold current and voltage for the resistance change is about 5.0×10 ^-5 A and 2.5V, respectively. The pulse voltage can also change the resistance and the pulse time is as shorter as 30ns for the resistance change. These properties of TiO_x/TiN_x film are comparable to that of conventional phase-change material, which makes it possible for RRAM application.