Energy control paradigm for compliance-free reliable operation of RRAM

Parasitic engineering for RRAM control

“…As expected, the initial decrease (devices D6 and D7) indicates that a larger and more robust filament is formed as the dissipated energy increases. This general behavior was also reported for compliance free ultra-short pulse (100 ps) forming experiments [7] where the dissipated energy is entirely composed of a step B overshoot transient. The subsequent increase (devices D5 and D8), we argue, is due to too much energy leading to a thermal dissolution (annealing) of the filament [12] similar to reports which detail a recovery of the reset state via local heating [13].…”

“…Increasing the current compliance, as well as the other aforementioned tactics, all tend to increase the randomness of the filament formation process. Recently, we demonstrated that filament stability correlates with the energy dissipated during forming and that there is an optimum for stability and endurance [7]. Insufficient current is merely an indicator of insufficient dissipated energy and thus incomplete filament formation.…”

“…DP represents a series of (1R) devices formed using ultra-short voltage pulses ranging from 10 ns to 130 ps in width. For all devices, the energy dissipated during forming was calculated as the product of the measured current, voltage, and duration as explained in detail in [7]. All the transient and the pulsed measurements are performed by applying voltage using 50 Ω terminated input probe tip to avoid the artifacts in the input voltage measurements due to reflections.…”

“…The current is then measured using the 50 Ω input impedance of a digital oscilloscope. Similar setup is described in detail in [6] and [7].…”

Impact of RRAM Read Fluctuations on the Program-Verify Approach

“…Spurning convention [4]–[6], the fast pulses are applied with a 50 Ω terminated probe with no current-limiting elements [12] as shown in Fig 1 (a). We rely on the ultra-short pulse timing to ensure that the energy delivered per pulse is small [13] and well controlled.…”