We demonstrate enhanced resistive switching (RS) stability, as measured by distribution, power consumption, and memory window, using different oxygen contents in a Ta oxide (TaOx) layer with a Pt top electrode and a TiN bottom electrode. The stability of the Pt/TaOx/TiN RRAM device increases as the oxygen contents of the TaOx layer increase. When oxygen is introduced during TaOx deposition, conventional bipolar RS (BRS) switches to self-compliant BRS, and distribution is improved within 200 repeated RS cycles. We investigate the conduction mechanisms for both a low resistance state (LRS) and a high resistance state (HRS). Ohmic conduction in the LRS and for the low bias region in the HRS corresponds to the conductive filament (CF) theory, while Poole–Frenkel (PF) conduction in the high bias region of HRS is the dominant conduction mechanism. A possible RS mechanism with oxygen ion drift is discussed.