We observed unipolar resistance switching in Pt/TaO x/Pt cells. We could make the cell have
the bipolar resistance switching by inserting a stoichiometric Ta 2 O 5 layer between Pt and
TaO x layers. Bipolar resistance switching in Pt/Ta 2 O 5/TaO x/Pt cells occurred reliably
without applying an external compliance current. With increase in the Ta 2 O 5 layer
thickness, the current value at the low-resistance state became decreased but the forming
voltage became increased. We could explain these intriguing phenomena using the …