Figure 4
(a) Pulse width experiments show the device can switch with ultra-fast 300 ps pulse width while achieving symmetry point convergence. (b) Different forming compliance currents for both HfOx and TaOx RRAM devices and the resultant number of states. When formed at lower compliance current for both HfOx and TaOx devices the number of states increases. (c) The approach for adjusting the compliance current during initial electroforming and subsequent set and reset voltage ranges explored for both HfOx and TaOx devices. (d) Symmetry point shift with pulse condition. For both HfOx and TaOx devices it shows lower negative pulse amplitude can lead to symmetry point shift up whereas high negative voltage can result in symmetry point shift down. (e) Analog switching conditions with a high number of states and low off-conductance. Inset shows using a semi-log plot that TaOx device conductance is ∼10× lower. (f) No. of states VS off conductance showing, both HfOX and TaOx devices show 15 states but only TaOx devices can achieve over 10 µS conductance.
